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TriRig Sigma Recall? Immediately stop using...
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 I guess this explains why they're out of stock... Hope Nick gets this taken care of soon...



Dear Sigma Customers,
You are receiving this email because you purchased a TriRig Sigma stem, and we are writing to you today to discuss a safety issue we have discovered with the Sigma stems.

We are going to issue brand new stems to all existing Sigma customers, free of charge. It is essential that you discontinue use of your current stems IMMEDIATELY to avoid injury. Replacement stems will be ready in the next 8-12 weeks, possibly sooner. If you cannot be without your bicycle during that time, you should IMMEDIATELY discontinue use of your current stem and use an alternate stem for the time being.

Please read this ENTIRE email, we need your response to the questions below in the next 15 days. Thank you!

Background on Safety
First of all, we want you to understand that we take product safety VERY seriously. All TriRig products are tested and certified under the most rigorous standards tests that exist for bicycles: the CPSC and CEN tests. However, despite our best efforts, potential safety issues arise. When that happens, we move to action immediately, which is exactly what has happened here. We've identified an issue, and we are taking action.

What is the issue?
Currently, stems are produced in a die cast mold using a casting aluminum alloy designated ADC12. We have discovered an issue where, in certain conditions, the cast parts can fatigue over time, causing a catastrophic fracture that results in failure of the stem. Recently, we received a report from a customer whose Sigma stem had failed, breaking clean through the 4mm-thick wall at the center of the stem, just aft of the top clamp part. We have received notice of two such failures to date.

What stems are affected?
All current Sigma stems are affected - both the Sigma Flat and the Sigma +35. We have only seen failures on the Sigma Flat, but we will also be replacing the Sigma 35's.

What have we done to address the issue?
In order to address this issue, all Sigmas going forward will be CNC machined from a solid block of aircraft-grade T6-7075 aluminum, which boasts much improved strength and fatigue properties compared to ADC12.
  • For customers of the Sigma Flat, the redesigned part is called the Sigma XF, and is pictured at the top of this email. We have also redesigned the Sigma XF with a wider overall profile, and a wider bolt stance, in order to provide greater grip on the handlebar while reducing the required torque on the handlebar clamp bolts. With less torque on the bolts, the Sigma XF experiences less overall stress, further reducing the loads on the part. The Sigma XF also has a few other changes. First is that the stem is now designed so that it can be flipped! One way it's flat, and has the same geometry as the original Sigma Flat. When flipped, the XF has an additional 20mm of stack and 10mm less of reach.
  • For customers of the Sigma +35, the replacement stem is called the Sigma N35, and will have the same overall shape and design as the original Sigma +35, but will also be CNC machined from T6-7075.
  • Most importantly, the new Sigma XF and Sigma N35 are stronger with improved reliability.


Is the new version of the Sigma heavier than the original?
The redesigned Sigma XF is approximately 45g heavier than the original Sigma Flat, owing to its wider overall design. To put it in perspective, that's about the weight of one nutrition gel packet.

The Sigma N35 is approximately the same weight as the original Sigma +35, since the size and shape are the same. T6-7075 is marginally heavier than the ADC12 casting metal, but it shouldn't affect the weight of the Sigma N35 by more than a few grams.

What happens next?
We are currently putting the new design through extensive fatigue and standards testing. Once the design is validated, we will proceed to mass production. Each one of you will receive a brand new Sigma, free of charge. We will be sending these out in the next 8-12 weeks, as soon as they're ready. And we will continue to update you on the production status in the mean time.
We need to be sure that the old Sigma stems are taken out of use IMMEDIATELY, so we need each stem to be shipped back to us. We will reimburse you for your shipping cost, so please provide proof of your shipping payment when the stem is returned.

Please send the stems to:

Nick Salazar, TriRig.com
3036 Greensborough Dr
Highlands Ranch, CO 80129
USA


What if I no longer feel confident with the Sigma? I don't want to own the newly designed versions.
We completely understand. If you would prefer to return your stem for a complete refund, you may do so. We will waive the usual return period limits, and waive the restocking fees. This replacement program is no fault of yours, so you shouldn't have to be stuck with a product you no longer want.
To be clear, you can choose a replacement OR a refund, but not both. We need your decision via email in the next 15 days.
Also, we're very humbled and proud to say that the first customer to inform us of a stem failure ... he's still planning to ride the new Sigma when it's available. It's that kind of devotion to our products that makes our customers special, and keeps us really motivated as a company. We cherish each of our customers, and will continue to make the coolest and most reliable products we can dream up.

Don't hesitate to ask any questions if you have them. We are working hard to take care of this issue quickly and with the least possible amount of inconvenience. Thanks for your patience.


http://us1.campaign-archive2.com/...53&id=be15168b22

-Alex

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Re: TriRig Sigma Recall? Immediately stop using... [bostonalex] [ In reply to ]
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Oh no. This is actually the second recall of the sigma -- I know, because I was one (of two, I think) of the people who suffered a catastrophic failure with the first model (ouch, that really hurt) but went with the replacement. Not thrilled to have to replace it, but certainly beats the alternative :-)

Aside from the obvious issues it's a pretty nice product.


--
When I channel my hate to productive, I don't find it hard to impress
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Re: TriRig Sigma Recall? Immediately stop using... [bostonalex] [ In reply to ]
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Really sucks he has to go through this, but it appears he's doing his best to make good.
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Re: TriRig Sigma Recall? Immediately stop using... [Pooks] [ In reply to ]
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Hope this isnt the type of blow that can take down a small company...
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Re: TriRig Sigma Recall? Immediately stop using... [bostonalex] [ In reply to ]
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This is the downside of a small company working that is creating big time products. Nick makes some amazing products but no way that he can put in the R&D that Trek, Specialized, Zipp can do. Puts himself at risk of this sort of thing happening.

I have his Speed concept clamps and love them but I realize that I am riding with a product that was basically made in someones basement. (my assumption, likely not the actual setup).
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Re: TriRig Sigma Recall? Immediately stop using... [jonahsdad] [ In reply to ]
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I'm super impressed with how he's handling it. He's making it right, already has the new products designed and in testing. I'll buy one when they're ready to go.

-Alex

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Re: TriRig Sigma Recall? Immediately stop using... [jonahsdad] [ In reply to ]
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jonahsdad wrote:
but no way that he can put in the R&D that Trek, Specialized, Zipp can do. Puts himself at risk of this sort of thing happening.

And even big companies like Trek have had recalls of this nature (Trek steerer tube comes to mind)



Kat Hunter reports on the San Dimas Stage Race from inside the GC winning team
Aeroweenie.com -Compendium of Aero Data and Knowledge
Freelance sports & outdoors writer Kathryn Hunter
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Re: TriRig Sigma Recall? Immediately stop using... [bostonalex] [ In reply to ]
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I actually have the stem. First I'm hearing of it. It's a great product especially with Di2 for cleaning up the front end. Looks like they want them back immediately. Wonder if we can keep them until the new one is ready and assume the liability ourselves?
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Re: TriRig Sigma Recall? Immediately stop using... [bostonalex] [ In reply to ]
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i agree this seems like a recall done right. cervelo and sram had big recalls recently and they handled them great. i think that's the measure of a company, when it performs well in a time of adversity.

my only question is the remedy: "all Sigmas going forward will be CNC machined from a solid block of aircraft-grade T6-7075 aluminum, which boasts much improved strength and fatigue properties compared to ADC12."

it would have thought a forged stem would have better fatigue properties than a stem machined out of billet. unless that billet was first smacked by a forging press.


Dan Empfield
aka Slowman
Last edited by: Slowman: Jun 16, 14 15:49
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Re: TriRig Sigma Recall? Immediately stop using... [Slowman] [ In reply to ]
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It will, but forging tooling requires a fairly large investment while CNC doesn't. The per piece cost of a forged part is much cheaper but you'll need to figure out the point at which the tooling pays off. A fully CNC'd stem is going to be much, much more expensive than a cast one. I wonder how the MSRP will go up.
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Re: TriRig Sigma Recall? Immediately stop using... [blackey] [ In reply to ]
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I asked him the same question. You can keep the old stem but you have to send it back before you can receive the redesigned one.
I'm going to ride it indoors on the trainer. I have no choice since my steerer tube is cut too low to use a standard stem now...



blackey wrote:
I actually have the stem. First I'm hearing of it. It's a great product especially with Di2 for cleaning up the front end. Looks like they want them back immediately. Wonder if we can keep them until the new one is ready and assume the liability ourselves?
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Re: TriRig Sigma Recall? Immediately stop using... [durk onion] [ In reply to ]
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i don't think a forging die would cost that much. especially if the die wasn't that precise. the CNC program, that's kinda pricey, i would think. upon reflection, however, the fact that it's in T6 condition probably obviates the need for the billet to be forged.

Dan Empfield
aka Slowman
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Re: TriRig Sigma Recall? Immediately stop using... [Slowman] [ In reply to ]
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Forging tooling definitely costs a significant amount more than a CNC program (at least in my experience. I'm only a few years out of college and have only worked at one job so it might not always be the case.) It also takes a long time to make tooling compared to CNC which still might need some special fixturing. However, the Sigma is lucky in the fact that it could be 2D forged unlike most other stems which need to be 3D forged to create the hollow center section. I'd still imagine that the number of stems sold is really low and it would take a significant amount of time to break even on tooling.

I'm not sure what you mean by "if the die wasn't that precise". I assume that they would need it to be decently precise if they don't want to make a 300g stem.

T6 just describes the way that the aluminum is heat treated, it doesn't necessarily mean that's it's not from a forged blank.
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Re: TriRig Sigma Recall? Immediately stop using... [Slowman] [ In reply to ]
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It is also getting a bit wider, which might help?


Slowman wrote:
i agree this seems like a recall done right. cervelo and sram had big recalls recently and they handled them great. i think that's the measure of a company, when it performs well in a time of adversity.

my only question is the remedy: "all Sigmas going forward will be CNC machined from a solid block of aircraft-grade T6-7075 aluminum, which boasts much improved strength and fatigue properties compared to ADC12."

it would have thought a forged stem would have better fatigue properties than a stem machined out of billet. unless that billet was first smacked by a forging press.



Kat Hunter reports on the San Dimas Stage Race from inside the GC winning team
Aeroweenie.com -Compendium of Aero Data and Knowledge
Freelance sports & outdoors writer Kathryn Hunter
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Re: TriRig Sigma Recall? Immediately stop using... [sp1ke] [ In reply to ]
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where did you see that you need to return the current stem to receive a new one? for the first recall, it was only a matter of waiting for a new stem to be shipped
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Re: TriRig Sigma Recall? Immediately stop using... [cyfac06] [ In reply to ]
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It's in the original email from TriRig:

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We need to be sure that the old Sigma stems are taken out of useIMMEDIATELY, so we need each stem to be shipped back to us. We will reimburse you for your shipping cost, so please provide proof of your shipping payment when the stem is returned.

Please send the stems to:

Nick Salazar, TriRig.com
3036 Greensborough Dr
Highlands Ranch, CO 80129
USA


cyfac06 wrote:
where did you see that you need to return the current stem to receive a new one? for the first recall, it was only a matter of waiting for a new stem to be shipped
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Re: TriRig Sigma Recall? Immediately stop using... [durk onion] [ In reply to ]
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"I'm not sure what you mean by "if the die wasn't that precise"."

the more precise you make the forging die the less you have to machine. but you still get the benefits of grain size/flow/alignment of the forging process.

back in the early and mid 1990s we went through a period where cranksets were machined rather than forged. and we had a lot of crank failures. it's not that machining cranks was bad, rather that starting with a forging and using machining as a finish process (machining in the pedal eye and other threaded holes, etc.) seemed to overtake the idea of cranks just machined out of a hunk of aluminum. the more dialed in the forging mold, the less you'd have to hog out of the forging through machining.


Dan Empfield
aka Slowman
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Re: TriRig Sigma Recall? Immediately stop using... [jackmott] [ In reply to ]
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"It is also getting a bit wider, which might help?"

i'm sure it does and it would. all the tririg stuff is conceptually stunning. i would imagine every now and then every company runs afoul of the problem in the bike business: the aerodynamic, mechanical and structural elements of bikes are so complex they defy mathematics. predicting what happens to a bicycle during the process of riding it is only slightly easier than predicting cloud patterns. that's why i - conservative and a bit of a coward by nature - am usually in favor of incrementalism when "fixing" what i don't like about a bike through the introduction of a new product.


Dan Empfield
aka Slowman
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Re: TriRig Sigma Recall? Immediately stop using... [Slowman] [ In reply to ]
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Not trying to be rude, I only see them saying the original was a die cast aluminum part, not a forging. Cast is just a molded part and from my experience as a machinist is never 100% reliable. To move from cast aluminum to 6065 is a huge step up in my opinion and would remove any worries in my mind.
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Re: TriRig Sigma Recall? Immediately stop using... [Slowman] [ In reply to ]
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Slowman wrote:
i agree this seems like a recall done right. cervelo and sram had big recalls recently and they handled them great. i think that's the measure of a company, when it performs well in a time of adversity.

my only question is the remedy: "all Sigmas going forward will be CNC machined from a solid block of aircraft-grade T6-7075 aluminum, which boasts much improved strength and fatigue properties compared to ADC12."

it would have thought a forged stem would have better fatigue properties than a stem machined out of billet. unless that billet was first smacked by a forging press.

Dan, from reading the recall it appears that the defect is in the casting process. Most probably due to microvoids/porosity during the casting process. It wouldn't take many voids or exclusions to dramatically reduce the absolute strength or fatigue life in a component.

As an engineer I would not have used a casting process for a stem OR used ADC12 as a material for a part like this. We cast with ADC12 and use it for cases and enclosures which don't undergo any real loading stresses.
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Re: TriRig Sigma Recall? Immediately stop using... [bostonalex] [ In reply to ]
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The redesigned Sigma XF is approximately 45g heavier than the original Sigma Flat, owing to its wider overall design. To put it in perspective, that's about the weight of one nutrition gel packet.

Exactly how much did the first one weigh that +45g is considered insignificant?
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Re: TriRig Sigma Recall? Immediately stop using... [commendatore] [ In reply to ]
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commendatore wrote:
Exactly how much did the first one weigh that +45g is considered insignificant?

It is heavy. It is not a weight weenie part!



Kat Hunter reports on the San Dimas Stage Race from inside the GC winning team
Aeroweenie.com -Compendium of Aero Data and Knowledge
Freelance sports & outdoors writer Kathryn Hunter
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Re: TriRig Sigma Recall? Immediately stop using... [jackmott] [ In reply to ]
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I wasn't criticizing, legitimately curious!
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Re: TriRig Sigma Recall? Immediately stop using... [commendatore] [ In reply to ]
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commendatore wrote:
I wasn't criticizing, legitimately curious!

Oh, didn't take it as such. Just legitimately letting you know it is heavy!

Maybe I will weigh one Weds.



Kat Hunter reports on the San Dimas Stage Race from inside the GC winning team
Aeroweenie.com -Compendium of Aero Data and Knowledge
Freelance sports & outdoors writer Kathryn Hunter
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Re: TriRig Sigma Recall? Immediately stop using... [bostonalex] [ In reply to ]
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As one of the persons that experienced a failure (V2), I can tell you that Nick is a stand up guy and has done this right. I have compassion for small operations/start-ups and harbor no resentment largely due to the fact that there was no shirking here whatsoever. I am glad the message was delivered in such a strong, professional, and timely manner given the potential consequences. I hope they get to the other side of this one intact and I am sure they will only be the better for it bringing their innovation to the market.
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Re: TriRig Sigma Recall? Immediately stop using... [sp1ke] [ In reply to ]
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thanks / duh - reading is fundamental...

Shucks - I was hoping to start a collection of Sigma stem christmas tree ornaments.
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Re: TriRig Sigma Recall? Immediately stop using... [Slowman] [ In reply to ]
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Slowman wrote:
i don't think a forging die would cost that much. especially if the die wasn't that precise. the CNC program, that's kinda pricey, i would think. upon reflection, however, the fact that it's in T6 condition probably obviates the need for the billet to be forged.

It is strictly a volume game....and I'm guessing based on TriRig's size, the CNC option is by far the cheapest option....or he would have been amortizing his tooling costs well beyond the life expectancy of the product.

back in the day, we designed a frame that had an integrated, structural piece that was supposed to be forged....but our projected volumes were pretty low and we couldn't justify the tooling costs. We then looked at a modified design that could use an extrusion, but that wasn't feasible so we have to go with a CNC piece. While not as strong as a forged part, it was similar (or superior) to a cast part and was the best option across the board.

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Re: TriRig Sigma Recall? Immediately stop using... [Slowman] [ In reply to ]
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Slowman wrote:
"It is also getting a bit wider, which might help?"

i'm sure it does and it would. all the tririg stuff is conceptually stunning. i would imagine every now and then every company runs afoul of the problem in the bike business: the aerodynamic, mechanical and structural elements of bikes are so complex they defy mathematics. predicting what happens to a bicycle during the process of riding it is only slightly easier than predicting cloud patterns. that's why i - conservative and a bit of a coward by nature - am usually in favor of incrementalism when "fixing" what i don't like about a bike through the introduction of a new product.

With all due respect, but in the case of loading on a stem (which is what is being discussed here), a small bit of time with an instrumented stem and a data acquistion system would get you all you need to know about the possible loadings to create an effective design. Apply a reasonable factor of safety, and the engineering is fairly routine...especially in this day and age of PC based analysis tools.

This is true of basically the entire bicycle as well. Some companies, such as Cervelo, have done such things for a long time now: http://www.cervelo.com/.../lab-vs-reality.html, and http://www.cervelo.com/...-reality-part-2.html

Those same CAD tools also make generating a CNC program fairly easy as well. Heck, there are online sources where all you do is upload your 3D CAD model and relatively cheaply (and quickly) have CNC machined parts returned to you. For example: http://www.protolabs.com/firstcut

Now then, your opinion on this may be colored by the fact that until just fairly recently, the level of true engineering in the bike industry was on a somewhat low scale (and in some pockets is still somewhat "seat of the pants")...so that's understandable. Even now though, and with large companies (cough...SRAM road discs...cough) I'm sometimes amazed at the lack of things common in other industries...such as not doing validation testing in thermal test chambers over the expected use environments, and instead relying on "test riders".

http://bikeblather.blogspot.com/
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Re: TriRig Sigma Recall? Immediately stop using... [Tom A.] [ In reply to ]
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"With all due respect"

i don't think you do give respect, and i don't mean you disrespect the people actually involved in bike manufacture and development, but i don't think you respect what actually happens in the field. i don't know when i've seen as many recalls in the bike business (let alone the car business). do you think SRAM does not employ engineers? or specialized? or cervelo? do you think engineering just got discovered? yes, the tools engineers used have advanced greatly over the last decade and a half, but let me ask you this, as a thought experiment: why do fatigue testing machines exist? why are they needed at all? are they needed at all?


Dan Empfield
aka Slowman
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Re: TriRig Sigma Recall? Immediately stop using... [Slowman] [ In reply to ]
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> why do fatigue testing machines exist? why are they needed at all? are they needed at all?

Answer: unmodeled dynamics.

Even million dollar finite element analysis programs running week-long simulations on supercomputers only crudely approximate a subset of the conditions a part may see in the chaos of the real world.

I can almost guarantee that the TriRig dude used SolidWorks or whatever to simulate a lifetime of hitting potholes with a super-stiff aluminum bike while being ridden by Lampre-kit guy, and then added a huge safety margin. But that's just a starting point.
Last edited by: trail: Jun 17, 14 9:44
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Re: TriRig Sigma Recall? Immediately stop using... [Slowman] [ In reply to ]
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Dan- It looks like Nick is saying the original stem was die cast, and not forged or machined...The new one looks to be machined. Traditionally in terms of fatigue strength Die Casting < Machined < Forged
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Re: TriRig Sigma Recall? Immediately stop using... [trail] [ In reply to ]
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"Answer: unmodeled dynamics."

aka unanticipated shit that happens. which is replete in the world of bike manufacture, because there are so many unanticipated or unquantifiable or even qualifiable or identifiable forces subject to a bike during cycling. further, even testing machines don't catch everything. as a bike maker we encountered failures in the field we could not duplicate in the lab, with testing machines.


Dan Empfield
aka Slowman
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Re: TriRig Sigma Recall? Immediately stop using... [pyrahna] [ In reply to ]
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"Traditionally in terms of fatigue strength Die Casting < Machined < Forged"

i am no expert. i am just an old ex maker of bikes and bike stuff. in my experience, just about everything is machined. nothing is JUST forged. that said, one big issue is what you machine it out of. i'm open to being educated here, but it seems to me nick is paying special attention to the underlying condition of the billet or block or thing that gets chucked up into the CNC mill, to a degree he previously did not. T6 condition of that 7000-series aluminum he's using is a stress relieved billet entering the machining process. starting with a forged blank and machining in the fine points, including threaded holes, precise holes for steerer and handlebar, is another typical and acceptable way.

in my experience, the parts of the bike that are subject to a lot of repeated twisting and loading in various axes, if they're made of aluminum, want to be forged. stems, cranks, derailleur bodies, hub flanges are good candidates. even then, some forged products are still not ready for end use. cranks, in the old squarehole days, needed to have their squareholes cut via a broach and coin process, to make the squarehole hard enough to withstand the pressure against the BB spindle. it was not really understood, during the 90s, why this was necessary, and a lot of up and coming crank makers found this out the hard way. along with their customers. me included.

nothing makes you an expert in the bike manufacturing business like failure. it also causes you to be very respectful of the methods and processes used by bike makers over the past century and more.


Dan Empfield
aka Slowman
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Re: TriRig Sigma Recall? Immediately stop using... [Slowman] [ In reply to ]
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Dan- I agree with everything you said about manufacturing and your understanding about how parts are made. The only thing I am unsure of is whether the sigma stems were cast (i.e. molton metal poured into a mold) and then machined to make them pretty and put in functional details like threads, or if they were cast (see previous description), then forged (heavy hammer coming down on cast part to align the grain in the metal), and then cnc'ed. I take it that you believe it was the second set of processes, but I don't see anything in the letter to indicate that there was a forging step. The forging step would add a lot of benefit for a part of this nature.
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Re: TriRig Sigma Recall? Immediately stop using... [pyrahna] [ In reply to ]
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"I take it that you believe it was the second set of processes"

no, i guess i didn't explain myself well. my original post to this thread was to question whether the better remedy to replacing these stems with a machined piece was to replace these stems with a forged piece (a secondary machining process being necessary to cut threads, etc.). my question is the use of machining as the major way to create the piece, in this particular application. it just did not work out so well in years past with cranksets. however, nick is starting with a properly conditioned metal (T6 7075) which i think addresses this concern to a significant degree. he's also spreading out the bolts from each other, and perhaps adding material high stress areas.


Dan Empfield
aka Slowman
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Re: TriRig Sigma Recall? Immediately stop using... [Slowman] [ In reply to ]
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Gotcha...I think I understand a little bit more where you are coming from.

In regards to manufacturing process affecting the material properties there are a couple aspects that effect the overall 'strength' (using this term generally) they are
material (i.e. chemical composition)
porosity (is there any air in the part)
hardness (how hard is it)
grain structure (are the particles in the material all aligned)

Nick appears to be switching the material to 7075 from ADC12, I have never played with ADC12 but going to 7075 has rarely been a bad move. He appears to be switching from a casting where the porosity COULD be an issue to a billet where it will almost certainly not be a factor. The hardness was not specified before and with a casting, unless it was heat treated afterwards, the hardness would assumed to be pretty low, but switching to a 'T6' (T stands for temper and the 6 is a specification call out) it will be a known quantity and will almost be certainly hard enough. Which takes us to grain structure. This is where forging can help significantly over a billet piece. Most, but not all, billets will be cold forged before selling it. The grain structure will all point in one direction depending on how it was forged. When you machine the billet you will be cutting across the grain structure and weakening the part slightly. When you forge the part into a close to final shape you will align the grains to go with the curves of the part, thereby strengthening the part.

This is all a simplification, and I'm sure someone will point out where I glossed over some details but I think it adds to the discussion overall.

In regards to the CNC'ed cranks of the 90's they were usually putting a soft CNC'ed aluminum crank and bolting it to a hardened steel spindle, and then wondering why the crank lost.
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Re: TriRig Sigma Recall? Immediately stop using... [pyrahna] [ In reply to ]
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"In regards to the CNC'ed cranks of the 90's they were usually putting a soft CNC'ed aluminum crank and bolting it to a hardened steel spindle, and then wondering why the crank lost."

the cranks of that era also lost the battle against hardened pedal spindles, and that is the battle they lost most often.

"
When you forge the part into a close to final shape you will align the grains to go with the curves of the part, thereby strengthening the part."

i referred to grain size and orientation in my posts further up, which is why forging is, to me, the preferred process when using aluminum in bikes in areas of repeated bending and twisting. used to be jo klieber (syntace) was the king of stem testing. he built his own testing machines and even competing stem makers would send their stems to him and he'd fatigue test them. assuming this is still the case, if i were a stem maker i'd send my stem over to jo and have him test my stem.

in fact, here you go, the red monster:




Dan Empfield
aka Slowman
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Re: TriRig Sigma Recall? Immediately stop using... [Slowman] [ In reply to ]
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Slowman wrote:

i referred to grain size and orientation in my posts further up, which is why forging is, to me, the preferred process when using aluminum in bikes in areas of repeated bending and twisting.

Sure forging has ideally the best material properties, but engineering is all about the compromises. First, actually getting those optimal properties from forging is not straightforward and there are many errors you can make in your forging process that may result in less than ideal properties. Second is obviously cost, forgings are just so expensive and CNCing aluminum is just so so much cheaper. Even in aerospace where we probably worry a bit less about cost than in cycling, there are some big machined aluminum pieces used, some even directly replacing a forged part. These parts are under all sorts of bending and twisting. Sometimes a forged part is replaced with a machined part that is even lighter, because of compromises in the design because it is forged. The speed that you can machine aluminum at is pretty spectacular. As long as it is designed properly a machined part would last as long as a forged part, assuming both are designed for the similar loads/lifetime.
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Re: TriRig Sigma Recall? Immediately stop using... [Slowman] [ In reply to ]
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Slowman wrote:
"With all due respect"

i don't think you do give respect, and i don't mean you disrespect the people actually involved in bike manufacture and development, but i don't think you respect what actually happens in the field. i don't know when i've seen as many recalls in the bike business (let alone the car business).


I apologize if you misunderstood...I must not have been clear that my expression of respect was aimed at you and that I was responding to the portion of your statement above that I put in bold which, if I may paraphrase, stated that the loading on a stem is not easily determined or able to be modeled. Actually...it is.


Slowman wrote:
do you think SRAM does not employ engineers? or specialized? or cervelo?

Of course they do. In fact, I linked above to some of their output, didn't I?


Slowman wrote:
do you think engineering just got discovered?

Of course not. But, as I also said above, there are still "pockets" (and surprisingly many of them in the bike industry) where the design process is basically "let's just try this and see what happens".


Slowman wrote:
yes, the tools engineers used have advanced greatly over the last decade and a half, but let me ask you this, as a thought experiment: why do fatigue testing machines exist? why are they needed at all? are they needed at all?

They should exist as design validation and process verification tools, NOT as design tools. If something is going to fail under fatigue loading, the likelihood of that should be established well ahead of that prior to building any test models using analysis tools (be it hand calculations or computer modeling, or both), and that likelihood reduced by design. Testers such as that should be used (like the thermal chamber I described above) to validate the design and to catch things such as manufacturing process errors and the like prior to a product being released to production.

http://bikeblather.blogspot.com/
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Re: TriRig Sigma Recall? Immediately stop using... [trail] [ In reply to ]
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trail wrote:
> why do fatigue testing machines exist? why are they needed at all? are they needed at all?

Answer: unmodeled dynamics.

I don't think that's correct. If you don't know the load case, how do you set up a fatigue tester to apply the loading?

Like I said above, it would be fairly easy to develop a fairly comprehensive load case for a bike stem. If you know the load case to set up a fatigue tester, then you have the load case to do modeling on as well.


trail wrote:
Even million dollar finite element analysis programs running week-long simulations on supercomputers only crudely approximate a subset of the conditions a part may see in the chaos of the real world.

I think using HALT/HASS testing may be more along the lines of what you were thinking...

http://bikeblather.blogspot.com/
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Re: TriRig Sigma Recall? Immediately stop using... [Tom A.] [ In reply to ]
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I'm not certain from where you are developing your thoughts on the state of engineering in the bike industry, but I can tell you from personal experience that it is wrong.

One of the companies I worked for tested EVERYTHING before we could spec it.....static load testing, fatigue load testing, etc. When we designed our own parts, they were "tested" digitally and then in our lab and then under riders.

Are there some companies who just spec stuff w/o testing them? Sure...same as any industry. But to say that engineering was something that was just recently discovered / employed by the bike biz is, quite frankly, laughable.

Chicago Cubs - 2016 WORLD SERIES Champions!!!!

"If ever the time should come, when vain and aspiring men shall possess the highest seats in government, our country will stand in need of its experienced patriots to prevent its ruin." - Samuel Adams
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Re: TriRig Sigma Recall? Immediately stop using... [Tom A.] [ In reply to ]
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"I apologize if you misunderstood"

you apologize if i misunderstood, or you apologize because you described your point inartfully? ;-)

"
They should exist as design validation and process verification tools, NOT as design tools."

i'd like to know whether the engineers in the bike business agree in principle with what you write above (i certainly do) but act at variance with this (i suspect they do).

the modifications made to this stem, both in material and in design (e.g., "
wider overall profile, and a wider bolt stance") are examples of the very failure of a product used as data points for a redesign. you mentioned that cervelo uses predictive computer modeling and that "the engineering is fairly routine" but i don't know if anybody - including anybody at cervelo - thinks this is routine or straightforward or easy. that's why everybody tests. no reputable bike brand relies on its engineering alone.

there is no reason for this "validation and verification" unless the modeling of a product's fatigue life is inexact or incomplete. let us say you modeled the aerodynamics of a bike, took it to the wind tunnel, along with putty. isn't the very fact that you brought putty using testing as a design tool? let's say that you engineered a part, tested it and, tho it should have been sound, it failed in the same place numerous times. what do you do? not use that information? go back and discover your engineering flaw and re-engineer the part? or do you just add more beef to that area?

i suspect and suggest most bike makers rely on the putty and the beef, because of the gap between how we think a bike should work and how it really does work. that's not to say that we don't start with engineering. it's just to say that it's not routine, it's not easy, and fatigue failures during testing expose the shortcomings in our engineering.

bike companies can't simply use engineering to fix the fatigue failures discovered during testing, because the very engineering upon which it relied failed to expose this weakness. so it adds beef to the area. or redesigns to inoculate the area against the failure. or changes the material. which is what nick is doing.

i'm interested to see how the bike engineers on the forum characterize the way they deal with a testing failure.


Dan Empfield
aka Slowman
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Re: TriRig Sigma Recall? Immediately stop using... [Tom A.] [ In reply to ]
Quote | Reply
 

>I don't think that's correct. If you don't know the load case, how do you set up a fatigue tester to apply the loading?

Attitudes like yours are why it's a "best practice" to make the testing/QA team totally independent from the engineering team. :)

A load case is an approximation. There's no way to capture all the possible vibrations/forces, etc, that could happen in the real world. I'm involved in this for military parts. We come up with mission profiles, often based on instrumentation during actual missions. Then design off those. Then run them through extreme testing on 3-axis shock-and-vibe tables (fun to watch), set to exceed the mission profile by a large margin, usually.

Then after that, the testing starts. And it can all go back to the drawing board. Because of technology the likelihood of going back to the drawing board is much lower. And cheaper. But it's pure hubris to think that it's the be-all, end-all.
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Re: TriRig Sigma Recall? Immediately stop using... [Power13] [ In reply to ]
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Power13 wrote:
I'm not certain from where you are developing your thoughts on the state of engineering in the bike industry, but I can tell you from personal experience that it is wrong.

One of the companies I worked for tested EVERYTHING before we could spec it.....static load testing, fatigue load testing, etc. When we designed our own parts, they were "tested" digitally and then in our lab and then under riders.

Are there some companies who just spec stuff w/o testing them? Sure...same as any industry. But to say that engineering was something that was just recently discovered / employed by the bike biz is, quite frankly, laughable.

Depends on your definition of "recent", no? Seeing as how I've been playing around with bikes now for >30 years, "recent" to me is more along the lines of in the last 15 years or so ;-) My thoughts are developed from my own personal observations.

"When we designed our own parts, they were "tested" digitally and then in our lab and then under riders." In other words, the load cases were defined, they were modeled, and then they were validated using test machines. Sounds good.

http://bikeblather.blogspot.com/
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Re: TriRig Sigma Recall? Immediately stop using... [trail] [ In reply to ]
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trail wrote:


>I don't think that's correct. If you don't know the load case, how do you set up a fatigue tester to apply the loading?

Attitudes like yours are why it's a "best practice" to make the testing/QA team totally independent from the engineering team. :)

A load case is an approximation. There's no way to capture all the possible vibrations/forces, etc, that could happen in the real world. I'm involved in this for military parts. We come up with mission profiles, often based on instrumentation during actual missions. Then design off those. Then run them through extreme testing on 3-axis shock-and-vibe tables (fun to watch), set to exceed the mission profile by a large margin, usually.

Then after that, the testing starts. And it can all go back to the drawing board. Because of technology the likelihood of going back to the drawing board is much lower. And cheaper. But it's pure hubris to think that it's the be-all, end-all.

Aaah...I see...it appears you were mistaking a fatigue tester (something like what Dan posted a pic of above) for something used for HALT/HASS testing.

I've participated in many random vibe/shock tests, so I'm well aware of how that is used ;-)

http://bikeblather.blogspot.com/
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Re: TriRig Sigma Recall? Immediately stop using... [Slowman] [ In reply to ]
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Slowman wrote:
"I apologize if you misunderstood"

you apologize if i misunderstood, or you apologize because you described your point inartfully? ;-)


Yes. Both. I apologized if I caused you to misunderstand BECAUSE I wasn't clear. I guess I wasn't clear again...


Slowman wrote:

"
They should exist as design validation and process verification tools, NOT as design tools."

i'd like to know whether the engineers in the bike business agree in principle with what you write above (i certainly do) but act at variance with this (i suspect they do).

the modifications made to this stem, both in material and in design (e.g., "
wider overall profile, and a wider bolt stance") are examples of the very failure of a product used as data points for a redesign. you mentioned that cervelo uses predictive computer modeling and that "the engineering is fairly routine" but i don't know if anybody - including anybody at cervelo - thinks this is routine or straightforward or easy. that's why everybody tests. no reputable bike brand relies on its engineering alone.


I would submit that those changes indicate this was possibly something that could have been "caught" prior to even prototype build with more thorough load case definition and modeling.


http://bikeblather.blogspot.com/
Last edited by: Tom A.: Jun 17, 14 13:22
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Re: TriRig Sigma Recall? Immediately stop using... [Tom A.] [ In reply to ]
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Well, seeing as how the testing I described above was our SOP back in the mid-late 90's, and the guy driving the procedures was a notable, lifetime industry vet, I'd say that goes well past your definition of "recent."

And as a side note, no matter how much we modeled and tested, we always were hit w/ surprises. Sometimes it was caught before production, sometimes not......but unexpected developments were pretty common.

Chicago Cubs - 2016 WORLD SERIES Champions!!!!

"If ever the time should come, when vain and aspiring men shall possess the highest seats in government, our country will stand in need of its experienced patriots to prevent its ruin." - Samuel Adams
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Re: TriRig Sigma Recall? Immediately stop using... [Power13] [ In reply to ]
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Power13 wrote:
Well, seeing as how the testing I described above was our SOP back in the mid-late 90's, and the guy driving the procedures was a notable, lifetime industry vet, I'd say that goes well past your definition of "recent."

And as a side note, no matter how much we modeled and tested, we always were hit w/ surprises. Sometimes it was caught before production, sometimes not......but unexpected developments were pretty common.

So...do you think those procedures were fairly common in the industry at the time, or do they stand out since they weren't? :-)

Were most of the surprises due to unexpected process issues, or were they actual "design flaws"?

http://bikeblather.blogspot.com/
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Re: TriRig Sigma Recall? Immediately stop using... [ktm520] [ In reply to ]
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ktm520, sorry to hear you had one that broke. How bad was it?

I got the last v2 Sigma three weeks ago. I wanted to see if it would let me convert my Shiv TT over to an aftermarket 31.8mm bar system to get more adjustability than the Shiv allows. It worked great for that. As far as I know it's the only stem out there that works with the Shiv TT - my Holy Grail.

  • I dialed in my position;
  • much tighter, lower and faster;
  • convinced I bought some speed;
  • raced it twice and beat guys that were beating me in my earlier races this season;
  • then I got the recall email;
  • took the stem off;
  • put the stock Shiv front end back on, and
  • wait for v3 to show up.
Nick's doing the right thing. I support that. As bummed as I am, he must be miserable.

Nick promised the new version will definitely work on the Shiv TT.
Quote Reply
Re: TriRig Sigma Recall? Immediately stop using... [Tom A.] [ In reply to ]
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While I think we were a bit "over zealous" in our testing procedures, I would say that it was more common than not. I base that on my experiences in other companies and dealing with component suppliers, etc.

I honestly can't remember the nature of many of the surprises, but there was usually a lot of "there is no way that should have happened".

Interesting side note - there was a stem / seatpost company that we would NOT spec....because their products always failed VERY quickly in our fatigue testing. I won't name the company, but it was a brand that is widely recognized to be "bullet proof" and very durable. But we couldn't use them....

Chicago Cubs - 2016 WORLD SERIES Champions!!!!

"If ever the time should come, when vain and aspiring men shall possess the highest seats in government, our country will stand in need of its experienced patriots to prevent its ruin." - Samuel Adams
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Re: TriRig Sigma Recall? Immediately stop using... [Tom A.] [ In reply to ]
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i think that you view product testing - fatigue testing, most notably - as valuable and necessary. no disagreement between us there. i think the gap between us is that you think the question of whether a bicycle product will fail before it's supposed to is knowable. i do not.

let me qualify. is it possible to know whether a fork is going to fail? or a crankset? a frame? a chain stay? stem? handlebar? no. yes, theoretically. yes, eventually. but not today.

what you have today in this industry is that razor thin margin between light weight and fatigue life. if you feel you need to make a 300g road fork, but it cannot fail, no, you can't simply engineer that with enough precision to anticipate all the stresses on that fork. to those who think they can, i submit it's only because you're starting with a design that stands on the shoulders, and benefits from, field testing, fatigue testing, ending in hundreds or thousands of fork failures over the past 25 years.

had an engineer the job today of designing a 300g bicycle fork that would stand up to 100,000 cycles (or however many cycles the industry is asking for these days) in a typical fork testing machine (as prescribed by ASTM or CPSC or whomever), without the aid of knowing how it is forks have evolved and how they're build today, not a chance in hell he could do it from behind his computer.

Dan Empfield
aka Slowman
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Re: TriRig Sigma Recall? Immediately stop using... [Slowman] [ In reply to ]
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Slowman wrote:
"Answer: unmodeled dynamics."

aka unanticipated shit that happens. which is replete in the world of bike manufacture, because there are so many unanticipated or unquantifiable or even qualifiable or identifiable forces subject to a bike during cycling. further, even testing machines don't catch everything. as a bike maker we encountered failures in the field we could not duplicate in the lab, with testing machines.

The other big variable that isn't being discussed is manufacturing/QC issues. You can build and test prototypes from supplier first samples all you want but it only takes one batch of die cast parts with porosity issues to lead to a rapid unanticipated failure.

The more I think about it the more I come to the conclusion that using a die casting process for a stem is borderline negligent. I can't believe that many engineers would chose that material and process for a critical component.
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Re: TriRig Sigma Recall? Immediately stop using... [ In reply to ]
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Hi, because of the second recall of the TriRig Sigma Stem iám checking possibilitis for a new Stem/Bar solution for my Shiv comp in black satin.

The big problem ist that i had to cut the steerertube realy low for the Sigma.

Can anybody tell me the stack of the original stem of the S-Works models?

The next big problem is that no new forks are available in europe, not even with a different paint, so if my steeretube is to low for any other stems i have to wait for the new Sigma, and that´s no solution for me because i don´t wana use this steme anymore.

Iám realy angry about this because it is the second time i can´t use my racebike in the midseason!!
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Re: TriRig Sigma Recall? Immediately stop using... [deirflu] [ In reply to ]
Quote | Reply
See if Dengfu will sell the FM087 Flat Stem Separately. Very similar steerer clamp requirements.


Quote Reply
Re: TriRig Sigma Recall? Immediately stop using... [Slowman] [ In reply to ]
Quote | Reply
Slowman wrote:
i think that you view product testing - fatigue testing, most notably - as valuable and necessary. no disagreement between us there. i think the gap between us is that you think the question of whether a bicycle product will fail before it's supposed to is knowable. i do not.

let me qualify. is it possible to know whether a fork is going to fail? or a crankset? a frame? a chain stay? stem? handlebar? no. yes, theoretically. yes, eventually. but not today.

IF the load case is properly measured/defined and the properties of the materials are well understood...then yes, in a statistical sense it is possible to determine the likelihood of failure of a particular component on a bike. Engineering like this is done on a daily basis, and has been done for a VERY long time.

Slowman wrote:
what you have today in this industry is that razor thin margin between light weight and fatigue life.

And I would submit that is a false dichotomy (i.e. "fool's choice") based on a misunderstanding of the driving performance factors of a bicycle ;-)

Slowman wrote:
if you feel you need to make a 300g road fork, but it cannot fail, no, you can't simply engineer that with enough precision to anticipate all the stresses on that fork. to those who think they can, i submit it's only because you're starting with a design that stands on the shoulders, and benefits from, field testing, fatigue testing, ending in hundreds or thousands of fork failures over the past 25 years.

had an engineer the job today of designing a 300g bicycle fork that would stand up to 100,000 cycles (or however many cycles the industry is asking for these days) in a typical fork testing machine (as prescribed by ASTM or CPSC or whomever), without the aid of knowing how it is forks have evolved and how they're build today, not a chance in hell he could do it from behind his computer.

Once again...IF the engineer or organization properly defines the use/load case, then YES it's possible to properly engineer a solution using well established principles and calculations. If not, then yes, one is confined to make/test/break/redesign.

That's where we seem to be hung up. Your opinion appears to me to be that the only way to get the knowledge of how a fork is used is to make and break a shit-ton of forks and empirically come up with "what works". I'm merely pointing out that this isn't so. It's also possible to FIRST use instrumentation to investigate/define the expected load case and then engineer a proper design. This is done every day in a myriad of industries, and in some cases where multiple prototypes and/or destructive testing isn't possible.

http://bikeblather.blogspot.com/
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Re: TriRig Sigma Recall? Immediately stop using... [Tom A.] [ In reply to ]
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"Your opinion appears to me to be that the only way to get the knowledge of how a fork is used is to make and break a shit-ton of forks and empirically come up with "what works"."

i don't disagree with you at all, theoretically. i'm just saying that in practice, in this industry, there's a gap between how engineers think a bicycle is ridden and how a bicycle actually is ridden. i am certain we will someday be able to predict weather patterns. there is an engineering solution to cloud prediction. we just don't have that solution yet. we're not there yet.

the difference between you and me is that you think engineers have figured bikes out. i know for an absolute fact that they haven't. do i think this means we dump engineering? no. i don't believe we dump engineering anymore than i believe we dump climatology. i'm saying there's a gap between engineering and real world cycling, and that gap is spanned by testing.

this isn't a binary choice between trial-and-error and engineering. you begin with engineering. you end with testing. when you test, and you are surprised and disappointed with your result because it does not comport with your expectations based on engineering, the result of the test generally informs the design changes you make (rather than going back and re-engineering the entire thing again).

as i have observed the bicycle business this is the typical chain of events. it's not that the trial-and-error guys overrule the engineers. it's that the engineers themselves end up with a final product based on the template i describe above. if i am mischaracterizing how it is that products in our industry come into being, i'm happy to hear from engineers and product managers that i'm behind that times.

this isn't to say that engineering always or usually falls short. i'm certain that in many or most cases you engineer a product and that product makes it right to market. but if it's something that might break, and might cause damage to the rider, that product is never brought to market through engineering alone. that product is ALWAYS tested, and if there is an early failure the nature of the failure informs the changes in product design, and it is at this point that the value of engineering lessens and trial-and-error now becomes the dominant design input.


Dan Empfield
aka Slowman
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Re: TriRig Sigma Recall? Immediately stop using... [Slowman] [ In reply to ]
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Slowman wrote:


the difference between you and me is that you think engineers have figured bikes out. i know for an absolute fact that they haven't. do i think this means we dump engineering? no. i don't believe we dump engineering anymore than i believe we dump climatology. i'm saying there's a gap between engineering and real world cycling, and that gap is spanned by testing.

this isn't a binary choice between trial-and-error and engineering. you begin with engineering. you end with testing. when you test, and you are surprised and disappointed with your result because it does not comport with your expectations based on engineering, the result of the test generally informs the design changes you make (rather than going back and re-engineering the entire thing again).

as i have observed the bicycle business this is the typical chain of events.

What he said.....

Chicago Cubs - 2016 WORLD SERIES Champions!!!!

"If ever the time should come, when vain and aspiring men shall possess the highest seats in government, our country will stand in need of its experienced patriots to prevent its ruin." - Samuel Adams
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Re: TriRig Sigma Recall? Immediately stop using... [Slowman] [ In reply to ]
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Engineering is a process...much like the scientific method. You take a best guess, you build it, you test it, and you discover why your best guess was wrong....so you loop back to the beginning with better assumptions than you started with and try it again. Computer aided design tools help shorten the amount of iterations this cycle takes before you get something you deem 'acceptable' but they do not eliminate this loop.
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Re: TriRig Sigma Recall? Immediately stop using... [Power13] [ In reply to ]
Quote | Reply
Interesting side note - there was a stem / seatpost company that we would NOT spec....because their products always failed VERY quickly in our fatigue testing. I won't name the company, but it was a brand that is widely recognized to be "bullet proof" and very durable. But we couldn't use them....

Oh come on! Will you tell me if I guess right? Are they still in business?

Quote Reply
Re: TriRig Sigma Recall? Immediately stop using... [Tom A.] [ In reply to ]
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>IF the load case is properly measured/defined and the properties of the materials are well understood...then yes, in a statistical sense it is possible to determine the likelihood of failure of a particular component on a bike. Engineering like this is done on a
>daily basis, and has been done for a VERY long time.

Right. But how do you do that? It's often an iterative process. In my experience we design something based on a load case, lab test it. Then we give it to a Marine. Marine breaks it in 5 minutes. So then you ask the Marine exactly what he was doing when it broke, and your mind is blown, because WTF, why would anyone do that? But then adjust the load case, and do a design iteration.

As Slowman says, sometimes you can nail it the first time, and it's all good. The holeshot. That's often the case for relatively mature, understood things. But often if you're doing something innovative - something with little-to-no existing real-world time - the likelihood of the holeshot decreases rapidly.

Computer stuff helps. It's evolutionary - maybe revolutionary - but, again,not the be-all, end-all.
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Re: TriRig Sigma Recall? Immediately stop using... [bostonalex] [ In reply to ]
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Hi everybody, this is Nick from TriRig. I used to post here as JudgeNick.

I want to thank Dan for letting me back onto the forum. I've been gone for a couple years, but glad to be back. I thought it would be nice for Slowtwitch forum members to be able to ask me questions here, since there is quite a bit of regular activity regarding my products. I'm happy to answer any questions you might have about the Sigma, how it was developed, what's going on right now, etc.

--
TriRig.com
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Re: TriRig Sigma Recall? Immediately stop using... [TriRig] [ In reply to ]
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TriRig wrote:
Hi everybody, this is Nick from TriRig. I used to post here as JudgeNick.

I want to thank Dan for letting me back onto the forum. I've been gone for a couple years, but glad to be back. I thought it would be nice for Slowtwitch forum members to be able to ask me questions here, since there is quite a bit of regular activity regarding my products. I'm happy to answer any questions you might have about the Sigma, how it was developed, what's going on right now, etc.

Nice, glad you're back in the door. Kudos for the way you guys have handled the issue.

-Alex

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Re: TriRig Sigma Recall? Immediately stop using... [TriRig] [ In reply to ]
Quote | Reply
TriRig wrote:
Hi everybody, this is Nick from TriRig. I used to post here as JudgeNick.

I want to thank Dan for letting me back onto the forum. I've been gone for a couple years, but glad to be back. I thought it would be nice for Slowtwitch forum members to be able to ask me questions here, since there is quite a bit of regular activity regarding my products. I'm happy to answer any questions you might have about the Sigma, how it was developed, what's going on right now, etc.

I am personally curious as to the root cause of the failure and any significant contributing factors.

Why did you chose a die casting process and ADC12 as a material? I also assume the castings are made in china or SE asia?

Kudos on doing the right thing and getting out in front of the issue. Always great to see.
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Re: TriRig Sigma Recall? Immediately stop using... [Pantelones] [ In reply to ]
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First off, I want to express a big, heartfelt THANK YOU for all the support you have all shown me in this thread, and throughout this forum over the years. I sincerely appreciate it, and it's really great to hear especially during this replacement process. Now, as to some of these questions:

Details about Failures:

For business reasons, I won't get into too much detail regarding the stem failure. As mentioned, we discovered that under certain conditions, the cast parts could fatigue and fail. Rather than attempt to "screen" which stems might pose a problem for which riders, we are simply replacing ALL of them.

Why Die Casting?
We originally chose to cast the stems because, after the initial cost of the die cast molds (which is considerable), we'd have the ability to make a lot of stems quickly, reliably, consistently, and with extremely high quality. Our past experience with cast parts (the Omega) has been an overwhelming success, further motivating the decision to cast the stems as well.

Why ADC12?
We originally chose ADC12 because it's one of the strongest aluminum casting alloys around. If you google the data sheet for ADC12, you'll find it's very similar to T6-6061, one of the most widely-used metals in all of cycling. That's the material used in the Omega brakes, and those have performed reliably for thousands of cyclists all over the globe, at every level of competition. Further, in order to maximize the properties of the metal and eliminate any microporosities/air deposits, we use the highest casting pressure our casting presses can take. That adds a little bit of time and cost, but helps make sure the ADC12 performs to its highest potential.

Why switch to T6-7075?
Our testing revealed that switching to machined stems versus cast stems would eliminate the fatigue and fracture problems the old design experienced. We could have simply moved to T6-6061, and that would have been sufficient to eliminate the problem. However, I wanted to go above and beyond what was simply necessary, and shoot for a higher standard of excellence. So we decided to use T6-7075, virtually the strongest and stiffest aluminum alloy there is. If you have a look at the data sheets for 6061 and 7075, respectively, you'll find 7075 is in a class all its own. In some categories, it boasts metrics at double or even triple the values for 6061. Using T6-7075 costs us quite a bit more, because the alloy is so hard that it requires longer machining time and more frequent bit replacements (and CNC bits are not cheap). But we really want to inspire confidence in our customers, and create the highest-quality products we can.

I know that this whole situation can be very inconvenient, and for that I personally apologize. But right now, my priority is keeping everyone safe, and making things right.

Thanks!

--
TriRig.com
Last edited by: TriRig: Jun 18, 14 19:17
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Re: TriRig Sigma Recall? Immediately stop using... [TriRig] [ In reply to ]
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TriRig wrote:
Using T6-7075 costs us quite a bit more, because the alloy is so hard that it requires longer machining time and more frequent bit replacements (and CNC bits are not cheap).

While I don't dispute the tool wear issue, a lot of machinists will say that machining 7075 is faster exactly because it is harder -- that is, it is less 'gummy' and the chips break more easily, allowing for deeper cuts and/or faster travel. You may want to talk with a shop that specializes in machining aerospace alloys (such as 7075 and 2024) because I'm sure they have processes that are optimized for them.
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Re: TriRig Sigma Recall? Immediately stop using... [asad137] [ In reply to ]
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Thanks. I apologize if I said something misleading about 7075. In general, you will find that it is ALWAYS more expensive to machine with 7075 versus 6061, simply due to material cost, if not machine time, bit wear, and other factors. Maybe it's "faster" in the opinion of some, but it's (almost?) universally more expensive. As far as TriRig is concerned, the difference in cost between 6061 and 7075 from our factory was not prohibitive. It was definitely more expensive, but easily worth it from my perspective. Personally, I've NEVER seen anyone quote a 6061 CNC job cheaper than a 7075 job.

--
TriRig.com
Last edited by: TriRig: Jun 18, 14 19:24
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Re: TriRig Sigma Recall? Immediately stop using... [TriRig] [ In reply to ]
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TriRig wrote:
Personally, I've NEVER seen anyone quote a 6061 CNC job cheaper than a 7075 job.

Sure, I can believe that. I'm just saying that's not due to cycle time, as 7075 is more machinable due to it being harder and having nicer chip properties. But, hey, don't take my word for it -- even the Aluminum Association rates 7075 as being more machinable than 6061.
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Re: TriRig Sigma Recall? Immediately stop using... [Jamaican] [ In reply to ]
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Jamaican wrote:
See if Dengfu will sell the FM087 Flat Stem Separately. Very similar steerer clamp requirements.

dengfubikes wrote:

  • Stem for FM087 = $60
  • Shipping to USA = $28 by EMS
  • Stem length = 75mm
  • Steerer tube length requirements: min 24mm, max 34mm


My steerer tube height = 22.5mm
Dust cover removed = 26mm


However, it appears that the FM087 drops down in front of the frame. I'm awaiting a response from Dengfu regarding the distance between the steerer tube and front of frame.


My NP3:





/Howie Nordström
Last edited by: lllusion: Jun 19, 14 10:54
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Re: TriRig Sigma Recall? Immediately stop using... [Slowman] [ In reply to ]
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Slowman wrote:
"Your opinion appears to me to be that the only way to get the knowledge of how a fork is used is to make and break a shit-ton of forks and empirically come up with "what works"."

i don't disagree with you at all, theoretically. i'm just saying that in practice, in this industry, there's a gap between how engineers think a bicycle is ridden and how a bicycle actually is ridden.


No...I'm saying (and provided links to examples) that some engineers have actually instrumented up a bike and determined the typical loadings as an INPUT into the design process. You stated that this is a difficult thing to determine. It's not...if you know how to using mechanical instrumentation. Especially for the case of the loading on a stem, as we are discussing here.

Slowman wrote:
the difference between you and me is that you think engineers have figured bikes out. i know for an absolute fact that they haven't.


Perhaps the ones you are familiar with haven't. But, I've already pointed you to examples to ones that DO figure out the loads and inputs.

Slowman wrote:
this isn't a binary choice between trial-and-error and engineering. you begin with engineering. you end with testing. when you test, and you are surprised and disappointed with your result because it does not comport with your expectations based on engineering, the result of the test generally informs the design changes you make (rather than going back and re-engineering the entire thing again).

as i have observed the bicycle business this is the typical chain of events. it's not that the trial-and-error guys overrule the engineers. it's that the engineers themselves end up with a final product based on the template i describe above. if i am mischaracterizing how it is that products in our industry come into being, i'm happy to hear from engineers and product managers that i'm behind that times.


You're making my case for me ;-) I'm sure what you have observed has been the dominant "process" in the bike industry for a long time. I've already stipulated that this was the case until relatively recently. However, nowhere above in those 2 paragraphs do you mention 2 things critical to the engineering process. First, you need to actually take measurements to determine the load case. This is the thing you claim is extremely difficult. I've already given you examples of how that is just not so. Go read the Cervelo links again. Second, AFTER the testing, you need to "close the loop" on the initial modeling to make sure that: a.) the test apparatus/protocol faithfully replicates the actual loading (again, see the Cervelo link...they found that the "industry tests" were lacking in that regard), and b.) if the results don't agree with the modeling, you need to determine what was missing or incorrect in the model so that the models can improve for future analysis. To not do so is to just condemn yourself to the crude "open loop" engineering process you described above.

Slowman wrote:
this isn'
t to say that engineering always or usually falls short. i'm certain that in many or most cases you engineer a product and that product makes it right to market. but if it's something that might break, and might cause damage to the rider, that product is never brought to market through engineering alone. that product is ALWAYS tested, and if there is an early failure the nature of the failure informs the changes in product design, and it is at this point that the value of engineering lessens and trial-and-error now becomes the dominant design input.


Resorting to just "trial and error" without understanding is merely tinkering, not engineering.

http://bikeblather.blogspot.com/
Last edited by: Tom A.: Jun 19, 14 18:48
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Re: TriRig Sigma Recall? Immediately stop using... [trail] [ In reply to ]
Quote | Reply
trail wrote:
>IF the load case is properly measured/defined and the properties of the materials are well understood...then yes, in a statistical sense it is possible to determine the likelihood of failure of a particular component on a bike. Engineering like this is done on a
>daily basis, and has been done for a VERY long time.

Right. But how do you do that? It's often an iterative process. In my experience we design something based on a load case, lab test it. Then we give it to a Marine. Marine breaks it in 5 minutes. So then you ask the Marine exactly what he was doing when it broke, and your mind is blown, because WTF, why would anyone do that? But then adjust the load case, and do a design iteration.

As Slowman says, sometimes you can nail it the first time, and it's all good. The holeshot. That's often the case for relatively mature, understood things. But often if you're doing something innovative - something with little-to-no existing real-world time - the likelihood of the holeshot decreases rapidly.

Computer stuff helps. It's evolutionary - maybe revolutionary - but, again,not the be-all, end-all.

To be clear, I've never said that modeling alone is sufficient.

In the case you mention above, how was the original load case defined? Did you take a similar device that was instrumented and let the Marines "play" with it?

http://bikeblather.blogspot.com/
Quote Reply
Re: TriRig Sigma Recall? Immediately stop using... [thethird] [ In reply to ]
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thethird wrote:
ktm520, sorry to hear you had one that broke. How bad was it?

I got the last v2 Sigma three weeks ago. I wanted to see if it would let me convert my Shiv TT over to an aftermarket 31.8mm bar system to get more adjustability than the Shiv allows. It worked great for that. As far as I know it's the only stem out there that works with the Shiv TT - my Holy Grail.

  • I dialed in my position;
  • much tighter, lower and faster;
  • convinced I bought some speed;
  • raced it twice and beat guys that were beating me in my earlier races this season;
  • then I got the recall email;
  • took the stem off;
  • put the stock Shiv front end back on, and
  • wait for v3 to show up.
Nick's doing the right thing. I support that. As bummed as I am, he must be miserable.

Nick promised the new version will definitely work on the Shiv TT.

well...not quite true.i built a stem specifically for the shiv TT with it's 1" steerer while also allows for use of 31.8 bars and features fully internal wiring that will enter the shiv TT frame without ever being exposed to air (from bar to stem to frame, with a slight frame mod) and have been racing it since 2012. machined 7075.

:)
Quote Reply
Re: TriRig Sigma Recall? Immediately stop using... [Tom A.] [ In reply to ]
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it seems to me that you're trying to bend this into a battle of two approaches: engineering versus trial-and-error. that's not how this industry works and that's certainly not how i've characterized it. i know most of the more senior engineers at most bike companies in the U.S., and i know how they work, and how they work is how i've described it. using your reasoning there is no need for wind tunnels, or fatigue and high impact testing machines. maybe that's what you believe, i don't know. but until all the loads and forces applied to all parts of a bike - by the wind, by the road, by the rider - are understood, the industry is going to keep doing things the way i describe (and i don't want to ride anything made by anybody who thinks his engineering knowledge alone is enough to make safe products). everybody tests. not only do they test, in many cases it's enshrined into law that they test. and were it not a legal requirement, they would still test, because the engineers in this industry (fortunately) are not so arrogant as to think their engineering knowledge supplants the need to test.


Dan Empfield
aka Slowman
Quote Reply
Re: TriRig Sigma Recall? Immediately stop using... [Tom A.] [ In reply to ]
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"To be clear, I've never said that modeling alone is sufficient."

i think that is certainly your implication. that is the take-away of many or most, if not all, of us who read your posts earlier in the thread. you write as if all the forces subjected to a bike and all its constituent parts are kind of like a species whose genome has been entirely mapped. the implication is that testing is therefore superfluous. it's pro forma. it's ministerial. nothing to learn here.


Dan Empfield
aka Slowman
Quote Reply
Re: TriRig Sigma Recall? Immediately stop using... [Slowman] [ In reply to ]
Quote | Reply
Slowman wrote:
it seems to me that you're trying to bend this into a battle of two approaches: engineering versus trial-and-error. that's not how this industry works and that's certainly not how i've characterized it. i know most of the more senior engineers at most bike companies in the U.S., and i know how they work, and how they work is how i've described it. using your reasoning there is no need for wind tunnels, or fatigue and high impact testing machines. maybe that's what you believe, i don't know. but until all the loads and forces applied to all parts of a bike - by the wind, by the road, by the rider - are understood, the industry is going to keep doing things the way i describe (and i don't want to ride anything made by anybody who thinks his engineering knowledge alone is enough to make safe products). everybody tests. not only do they test, in many cases it's enshrined into law that they test. and were it not a legal requirement, they would still test, because the engineers in this industry (fortunately) are not so arrogant as to think their engineering knowledge supplants the need to test.

What? I am most certainly not and have never even implied it's either/or. That's something you've been putting forth, not me. In fact you yourself above in post#52 said that "i think that you view product testing - fatigue testing, most notably - as valuable and necessary. no disagreement between us there."

I haven't said anything in between then and now which stated or implied anything different. So why do you now think I hold the opinion that testing is completely unnecessary? I get the feeling you haven't been thoroughly reading my replies.

Let me sum up. You said "mechanical and structural elements of bikes are so complex they defy mathematics." I would like to see if others with structural engineering backgrounds agree or disagree with your claim. I certainly do not, especially in regards to the loads on a stem.

http://bikeblather.blogspot.com/
Quote Reply
Re: TriRig Sigma Recall? Immediately stop using... [Slowman] [ In reply to ]
Quote | Reply
Slowman wrote:
"To be clear, I've never said that modeling alone is sufficient."

i think that is certainly your implication. that is the take-away of many or most, if not all, of us who read your posts earlier in the thread. you write as if all the forces subjected to a bike and all its constituent parts are kind of like a species whose genome has been entirely mapped. the implication is that testing is therefore superfluous. it's pro forma. it's ministerial. nothing to learn here.

Try reading what i actually write. What you are doing now is basically just setting up a bunch of strawmen.

http://bikeblather.blogspot.com/
Quote Reply
Re: TriRig Sigma Recall? Immediately stop using... [Tom A.] [ In reply to ]
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here is what you said:

"a small bit of time with an instrumented stem and a data acquistion system would get you all you need to know about the possible loadings to create an effective design. Apply a reasonable factor of safety, and the engineering is fairly routine...especially in this day and age of PC based analysis tools... This is true of basically the entire bicycle as well."

your view is that testing is only a validation of engineering, and that testing failures should not be inputs into the design process. you singled out cervelo as a company that operates in the way you describe. i would be shocked if damon rinard or any of cervelo's engineers agrees with you that failures in testing should not be taken into consideration during the design process.

the reason we have oversized bottom bearings in fork crowns can be traced back to repeated failures in testing just above the crown, confounding the engineering. you think this design paradigm is "tinkering", which i interpret as an amateurish approach to product design. cervelo has a little experience in fork and stem failures - as do trek and, well, most companies that have been making these products a long time - and i am quite confident these bike companies consider such failures design inputs.


if bikes enjoyed a stasis in design, yes, you would be right, most of what we need to know about the forces applied to a bike would be knowable and we'd design with ultimate confidence. but that's not the case. the minute you change a hub flange design, or use straight pull spokes instead of elbow-style spokes, or change the epoxy that holds 2 things together, or put bosses in the top of your top tube, or a hydration system inside your down tube, you introduce unknown unknowns.

i know one fork maker, early in the carbon fork days, who had it all figured out. it engineered its fork expertly, figuring out all the loads, all the stresses, and it tested its forks to make sure they would pass, and they passed. and then came the failures in the field, because there was one force this company forgot to consider: what happens during braking. the engineers just didn't think about this. they forgot. it never occurred to them. that's why you test.
it's not just to validate your superb engineering, so that you can high five everybody when you do your victory lap. it's because sometimes you aren't as smart as you thought you were. and when you have that failure, you're a fool if that failure does not inform the changes you must make in your design.

Dan Empfield
aka Slowman
Quote Reply
Re: TriRig Sigma Recall? Immediately stop using... [Slowman] [ In reply to ]
Quote | Reply
Slowman wrote:

your view is that...testing failures should not be inputs into the design process.

Nope. Never said that. In fact, if you look above you'll see where I said that testing failures feed back into determining what was missed in the modeling: "
..if the results don't agree with the modeling, you need to determine what was missing or incorrect in the model so that the models can improve for future analysis." Validation is of the modeling as well as the actual part.


Slowman wrote:

i know one fork maker, early in the carbon fork days, who had it all figured out. it engineered its fork expertly, figuring out all the loads, all the stresses, and it tested its forks to make sure they would pass, and they passed. and then came the failures in the field, because there was one force this company forgot to consider: what happens during braking. the engineers just didn't think about this. they forgot. it never occurred to them.

Gee...I wonder if they'd instrumented up a fork and ridden it around awhile during the load definition phase if they might have caught that braking load ommission? :-/


Slowman wrote:
that's why you test.
it's not just to validate your superb engineering, so that you can high five everybody when you do your victory lap. it's because sometimes you aren't as smart as you thought you were. and when you have that failure, you're a fool if that failure does not inform the changes you must make does not inform the changes you must make in your design.

Never said that either. Of course any testing failures inform changes in the design. But, they also inform changes in the modeling so that failures are less and less likely in future designs.


http://bikeblather.blogspot.com/
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Re: TriRig Sigma Recall? Immediately stop using... [pyrahna] [ In reply to ]
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Quote:
but going to 7075 has rarely been a bad move

Many (most) mil-aero OEMs don't allow 7075-T6 for use in structural applications (anything other than sheet form). We'd generally opt for 7050.
Quote Reply
Re: TriRig Sigma Recall? Immediately stop using... [Tom A.] [ In reply to ]
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"Nope. Never said that."

maybe i just misunderstood you when you said that testing should be for validation,
"NOT as design tools". can you again apologize if i misunderstood? ;-)


i'm not sure, but i think i can narrow the difference between our views to how it is engineers respond to failures. i think your view is that even if the engineering suggests a part will not fail (let's stay the area of a stem's attachment to the steerer), if it fails in testing you go back and see what you did wrong in your engineering. that is the only solution - find your engineering problem, find your modeling problem, remodel the part, retest the part. if it breaks again, find your modeling problem, rinse, lather, repeat. i'm saying that when you're on the razor's edge of safety and performance, you might find that there's a gap you can't bridge because there's something that happens that you can't anticipate.

i will concede you this: it's much easier to match engineering with testing, if you make your own testing tools (or you understand how somebody else made your testing tool) and your testing tool is fairly rudimentary. it's much more likely that you're going to have this gap between real life and life explained by engineering in the field, because there's a gap between what we think will happen to a bike (or a bike part) and what does happen to it (or, if the testing apparatus you're using is artfully built, very complex, and very good at replicating what happens in the field).

this is one of the problems in our industry. i had a specific part failure at merlin, a machined seat stay part breaking in the field, our industry standard test machine could only break a chain stay, we never broke a chain stay in the field, just a bunch of machined triple clamps (turning 2 seat stays into a monostay). the test machine never broke a triple clamp. you can't engineer properly what you don't yet understand and when that's the case, it's the failures that inform the design process directly, bypassing the engineering.


Dan Empfield
aka Slowman
Quote Reply
Re: TriRig Sigma Recall? Immediately stop using... [CW in NH] [ In reply to ]
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Can you explain why? I have no experience in mil-aero.... but in my industry we use 7075-T6 a decent amount.
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Re: TriRig Sigma Recall? Immediately stop using... [Slowman] [ In reply to ]
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Re: TriRig Sigma Recall? Immediately stop using... [pyrahna] [ In reply to ]
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Stress corrosion cracking, you can read a bit of the background here, but every mil-aero prime I've worked with prohibits 7075 in anything >=0.25" thickness (i.e. other than sheet). 2024 is also not allowed.
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Re: TriRig Sigma Recall? Immediately stop using... [CW in NH] [ In reply to ]
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Thanks for the link. Learned something today. That also explains why we don't mind using it in the industry I am in...low service life and much shorter times between regular cleaning and inspecting parts.
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Re: TriRig Sigma Recall? Immediately stop using... [Tom A.] [ In reply to ]
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you're calling uncle? or you think i'm calling uncle?

Dan Empfield
aka Slowman
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Re: TriRig Sigma Recall? Immediately stop using... [Slowman] [ In reply to ]
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Slowman wrote:
you're calling uncle? or you think i'm calling uncle?

I called Uncle. You obviously don't understand the role of measurement in the design process. I'm tired of repeating myself...

http://bikeblather.blogspot.com/
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Re: TriRig Sigma Recall? Immediately stop using... [Tom A.] [ In reply to ]
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"You obviously don't understand the role of measurement in the design process."

in the last 15 years of the 20th century, quite a few people entered the bike business who believed as you believe today, that, as you said, "
the engineering is fairly routine...this is true of basically the entire bicycle as well."

these people were far more dangerous to end users than were the "tinkerers", because the tools for engineers back then weren't nearly as advanced as they are today, and because a century of tinkering had given us bikes that did not break. until 1985 or so. that's when weight really became an imperative. we had a lot of bike and bike part failures in the 90s because the engineering was incomplete, and the engineers built testing machines that matched their knowledge of stresses on a bike - which was incomplete.

today, engineering is an imperative in bike design because the weights are really down to the nub. you can't be a tinkerer anymore. (why you insist on implying that i am anti-engineering is god's own mystery. i said the opposite a number of times.)

today it's the opposite. the tinkerers are now a bigger hazard than th
ose in the industry who think "engineering [for 'the entire bicycle'] is fairly routine", when you're talking about forks, stems, cranks, handlebars. but if you look at the failures in these parts, they are as likely, or more than likely, to come from companies who employ top rate engineers. why? because the engineering is not routine.

we are now in the state of perpetual recall. we are always in the middle of a recall from a major company employing expert engineers and big testing budgets. the very best engineers i know in this business are those who blend excellence in their craft with the humility that comes from acknowledging that engineering for bikes is not fairly routine.


Dan Empfield
aka Slowman
Quote Reply
Re: TriRig Sigma Recall? Immediately stop using... [CW in NH] [ In reply to ]
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For the love of god, all you "engineers" keep stating 7075-T6. Really? How thin is this stem going to be?

7075-T651. Block material, not sheet metal.

It is the core of all aerospace. The majority of parts, including structure, are made of aluminum. 7075 being the most often used.

We are a machine shop and we make parts for the aerospace industry.

But if you're going to throw around specs on material, the correct material is 7075-T651.
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Re: TriRig Sigma Recall? Immediately stop using... [tetonrider] [ In reply to ]
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I remember those posts, but I missed out on it. Have any to sell?
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Re: TriRig Sigma Recall? Immediately stop using... [prattzc] [ In reply to ]
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I could have been pedantic with the OP too, but its pretty clear that I understand the forms when I specifically addressed them. On an actual drawing, 7075-T651 would not be good enough either, you'd also need the QQ or AMS spec and the material basis. There's also no such thing as block material, as you know.

All of which is besides the point. 7075-T6XXX is prohibited for use (in the procurement specs) in anything but sheet form in structural applications or applications that require corrosion resistance, on most platforms, including both the military and commercial arms of Boeing, LM, NG, Airbus and GA.

7075 has been largely replaced by 7050, although I think that its more of a PIA to machine... There are of course exceptions, and a deviation would need to be sought for each such case.

So, in the case of a bicycle stem, that is a structural application, that is covered in sweat, there are better choices.
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Re: TriRig Sigma Recall? Immediately stop using... [CW in NH] [ In reply to ]
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For vertical lift, we seem to use a lot of it. Of course, most our parts are not exposed to the elements and are internally based.

I'm pretty sure Cnc machined 7075-t651 with a plating and paint would be more than adequate for a bike stem. Heavy as hell in comparison to forged or die, but pretty bomb proof.

And we still calm it blocks when we procure material. Call us barbaric.
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Re: TriRig Sigma Recall? Immediately stop using... [prattzc] [ In reply to ]
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Quote:
And we still calm it blocks when we procure material. Call us barbaric.
Just trying to match snark :)
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Re: TriRig Sigma Recall? Immediately stop using... [CW in NH] [ In reply to ]
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The world is ending, an engineer with a personality....

Noted!!!
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Re: TriRig Sigma Recall? Immediately stop using... [Slowman] [ In reply to ]
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Regarding the material choice, we are using T6-7075 because of its excellent mechanical properties, and also because it has far exceeded all of our testing protocols (and easily surpassed both the CEN and CPSC standards tests as well). All of our stems are ALSO coated with an electrolysis process (a type of anodizing) that adds additional corrosion-resistance to the part. We are confident that there will be ZERO failures with the new stems, period.

In my experience there are ALWAYS unknowns in real-world engineering, despite the best efforts of the engineer.

I agree with Tom that, theoretically, the load cases and engineering parameters of any part can be accurately and completely identified. But I also agree with Dan that even the best engineers DO NOT identify them all, even with the highest levels of knowledge, experience, and diligence. There will always be a gap between practice and perfection. But TriRig is committed to closing that gap with all of our efforts.

--
TriRig.com
Last edited by: TriRig: Jun 20, 14 21:14
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Re: TriRig Sigma Recall? Immediately stop using... [TriRig] [ In reply to ]
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Only other quality check I can think of is to have each piece sent for MPI or FPI to check for micro abrasions. The anodize should be fine for corrosion. A quick paint and poly coat would seal the deal. Powder coat would be a nice touch!!

If I were to make this part, I put the cost per piece based on a qty of 100pcs around $200. Material is inexpensive and easy to get. One time charge for 5 axis machining (to reduce fixtures) Cnc programming, cmm inspection programming, and fixtures, are pretty expensive but can be spread over the 100pc lot. The machine time is expensive too as you will likely set this up in a 5 axis and make 1-4 pcs at a time. Gets more expensive if put in 3 axis machine with more fixtures. Deburring and buffing or sand blasting or bead blast will be a lot charge. Mag or fluorescent inspect, anodize, prime, will be a per piece price based on size.

This is not a cheap fix for you nick, nor is it easy to raise the quality flag in yourself. I didn't take liberties at condemning you in the other thread regarding your customer service as I've had mixed emotions as a consumer of many omegas and an alpha. But this call to action trumps any disappointment I've had in past communications. I applaud your efforts on this.

Now, please double check the stress on the alpha, I love that damn bar and I really don't want to see that pop up on a thread like this!!! No way I want that in a Cnc milled aluminum version.

Good job nick. And good job dan for letting nick come on the forums again to post the info.
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Re: TriRig Sigma Recall? Immediately stop using... [prattzc] [ In reply to ]
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I'm looking for some input on what folks are using as an interim replacement .. are there any stems that use the same amount of steerer tube as the Sigma? If not what have folks rigged up (no pun intended)?
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Re: TriRig Sigma Recall? Immediately stop using... [cyfac06] [ In reply to ]
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The syntace flatforce looks close in height.
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Re: TriRig Sigma Recall? Immediately stop using... [Runless] [ In reply to ]
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hmm... I wonder if the flatforce would work based on the spec's below? I think the Sigma uses 22mm of steerer height?

It may be moot as the flatforce is a MTB stem that appears to come mostly in very stubby / short lengths and does not appear to be widely available either?

Steerer Height 27 mm (55 mm) Minimum Insert (steerer) 22 mm
Quote Reply
Re: TriRig Sigma Recall? Immediately stop using... [cyfac06] [ In reply to ]
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It comes in lengths up to 111mm(longer than the sigma) and appears to available through QBP(i.e. any bike dealer).

Anyways, a person with a slammed sigma may have too short of a steerer but if a person had a spacer of a few mm, it should work, I think.
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Re: TriRig Sigma Recall? Immediately stop using... [cyfac06] [ In reply to ]
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Here is my solution to the Sigma problem:



I got a friend who has a lathe to make the two pieces for me. I must stress that I have not used it yet, and anyone who copies this design does so at their own risk. But I am posting it immediately because I know some people will be really struggling for an immediate solution and may want to get on with having something similar made as soon as possible.

The piece on the left is intended to be bonded into the steerer. The grooves on the lower outer surface are to improve the ability of adhesive to retain it in the steerer. It has an M6 thread that goes all the way through the centre, and a larger female thread at the top to allow the piece on the right to be screwed into it. The idea is that the piece on the left will be used on its own when the Sigma replacement is received.

The piece on the right also has an M6 thread all the way through, and a larger male thread protruding from the bottom to allow it to be attached to the piece on the left. With this in place, a conventional stem can be used until the replacement Sigma is received. Note that it is only intended to support a stem where the steerer comes to around halfway up the stem clamp, it is not intended to have a stem clamped entirely or mostly on the extender. As I said, if you want to get something similar made and use it yourself, you do so at your own risk.

The friend who made this for me doesn't want to make production quantities for other people, so you're on your own for getting someone to make something similar for you.

The lower part could also be made using an expanding bung similar to existing commercial products, but it would have been much more complex for my friend to make, and I have a TT tomorrow that I want to use this for, so simplicity won. I'm happy enough to have it bonded in, as together with the extending piece, it covers all my expected use cases. The extending section protrudes far enough above the stem that a HED lollipop can be attached to replace the Sigma's bottle mount.

The total weight is 96g, and it's made from this alloy:
http://www.aalco.co.uk/...6T651-Plate_148.ashx
I'm not specifically recommending that, it's just what he already had, but it seems reasonably suitable, with good strength and corrosion resistance.
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Re: TriRig Sigma Recall? Immediately stop using... [Steve Irwin] [ In reply to ]
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Jeepers! A+ for effort, at least. hope it works for you !?
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Re: TriRig Sigma Recall? Immediately stop using... [cyfac06] [ In reply to ]
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Used it for a 50 mile TT yesterday. Front end seemed rock solid, and I drew a line down it with a marker so I could see afterwards if anything had moved relative to anything else, and no movement was evident.
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Re: TriRig Sigma Recall? Immediately stop using... [Steve Irwin] [ In reply to ]
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I'm not a Sigma owner, just an admirer of ingenious DIY solutions like this. Chapeau!

CodyBeals.com | Instagram | TikTok
ASICS | Ventum | Martin's | HED | VARLO | Shimano | 4iiii | Keystone Communications
Quote Reply
Re: TriRig Sigma Recall? Immediately stop using... [prattzc] [ In reply to ]
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Hello prattzc and All,

What are your thoughts on using titanium for the part?

Overall it would be a) heavier and but b) less material could be used because of the increased strength .... corrosion resistance is good.

How much more costly would you estimate the manufacture of small bicycle parts from titanium rather than aluminum in small lots?

Cheers,

Neal

+1 mph Faster
Last edited by: nealhe: Jun 29, 14 16:02
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Re: TriRig Sigma Recall? Immediately stop using... [nealhe] [ In reply to ]
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Titanium is much more expensive (both to purchase and to machine) than aluminum. For something like a stem I would expect it to be 2-3x the cost of 7075.
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Re: TriRig Sigma Recall? Immediately stop using... [TriRig] [ In reply to ]
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Will the Sigma XF have the same minimum steerer tube requirement?
I measure the current minimum to be19mm.

/Howie Nordström
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Re: TriRig Sigma Recall? Immediately stop using... [lllusion] [ In reply to ]
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Yes, the Sigma XF (replacement for Sigma Flat) has the same steerer-tube clamping zone. The Sigma N35 is identical to its predecessor (the Sigma 35) in all respects other than material.

--
TriRig.com
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Re: TriRig Sigma Recall? Immediately stop using... [TriRig] [ In reply to ]
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Hey Nick,
Any update on the new Sigma? Please save my butt from doing another 5h trainer ride!
Thank you!
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Re: TriRig Sigma Recall? Immediately stop using... [sp1ke] [ In reply to ]
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Hi sp1ke, we're working hard to get these finished. Thanks for your patience, and sorry for the inconvenience.

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TriRig.com
Last edited by: TriRig: Jul 28, 14 15:05
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Re: TriRig Sigma Recall? Immediately stop using... [TriRig] [ In reply to ]
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Just got a refund from TriRig for the Sigma I sent back. Replaced it in order to train and race, then decided to keep using the new stem vs. having a spare.


Road a bit (climbing & leap frogging) with a guy during IMCanada yesterday who was fully kitted with TriRig parts on his new P3, even had the Sigma 35 still on the bike.

/Howie Nordström
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Re: TriRig Sigma Recall? Immediately stop using... [TriRig] [ In reply to ]
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TriRig wrote:
Hi sp1ke, we're working hard to get these finished. Thanks for your patience, and sorry for the inconvenience.

So, so ready... How about a beta test? ;-)

-Alex

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Re: TriRig Sigma Recall? Immediately stop using... [TriRig] [ In reply to ]
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> Replacement stems will be ready in the next 8-12 weeks, possibly sooner.

It has now been 8 weeks since the mail, could we please get some more details about the replacements. Sooner didn't work out, but what are we looking at now, shipping next week, end of month or what? I just want to use my tri bike again, need that stem. Got new wheels and all...
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Re: TriRig Sigma Recall? Immediately stop using... [acco] [ In reply to ]
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Have you not been riding because you're waiting for a stem? Go pick up a $15 take off from your lbs.

____________________________________________________

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Re: TriRig Sigma Recall? Immediately stop using... [boostedcvc] [ In reply to ]
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I've been using my cyclocross bike lately. But, I would like to start using the tri bike, on which I had a slammed Sigma. Not enough steerer tube to mount a regular stem.

Anyway, think an update from TrRig would be in place.
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Re: TriRig Sigma Recall? Immediately stop using... [acco] [ In reply to ]
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That makes sense.

____________________________________________________

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Re: TriRig Sigma Recall? Immediately stop using... [acco] [ In reply to ]
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An important announcement will be sent via email some time this week :-)

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TriRig.com
Last edited by: TriRig: Aug 10, 14 14:46
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Re: TriRig Sigma Recall? Immediately stop using... [TriRig] [ In reply to ]
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Is the stem cover / cap thingy on the new Sigma flat compatible with the old one on the recalled stem? I've got my shift cables routed through it (see pic below) and was wondering if I could avoid recabling when I install the new stem.
Thanks!

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Re: TriRig Sigma Recall? Immediately stop using... [sp1ke] [ In reply to ]
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Unfortunately, not. The Sigma Flat cover is not compatible with the Sigma XF. You may be able to avoid a recabling if you're handy with a saw or dremel -- you could cut across the stem cover in this spot, freeing your cables:


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TriRig.com
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Re: TriRig Sigma Recall? Immediately stop using... [TriRig] [ In reply to ]
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TriRig wrote:
An important announcement will be sent via email some time this week :-)

Got it. Thanks!
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Re: TriRig Sigma Recall? Immediately stop using... [acco] [ In reply to ]
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Are the new ones available?
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Re: TriRig Sigma Recall? Immediately stop using... [kppolich] [ In reply to ]
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You should probably send in the old one first.
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Re: TriRig Sigma Recall? Immediately stop using... [acco] [ In reply to ]
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Yep, acco has it right. As we've consistently stated from the very beginning, we MUST have your old stem back (or proof of its destruction) before your replacement stem will ship. I know this isn't fun or convenient for anyone, and I apologize. But there are no exceptions here.

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TriRig.com
Last edited by: TriRig: Aug 19, 14 10:00
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Re: TriRig Sigma Recall? Immediately stop using... [TriRig] [ In reply to ]
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Got mine new stem in the mail yesterday. Even though it was a pain switching and waiting TriRig had great customer service during this issue.
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Re: TriRig Sigma Recall? Immediately stop using... [triromad] [ In reply to ]
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Finally got mine, well done Nick. Especially like that there are separate screws for cover and BTA.


Last edited by: acco: Aug 31, 14 13:44
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Re: TriRig Sigma Recall? Immediately stop using... [triromad] [ In reply to ]
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Got mine on Friday, playing around with the installation right now.

Damn, that's a short steerer tube cut... Like 22mm above the headcap. Oof...

-Alex

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