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Re: Garmin Vectors Going Prime-Time [power2max] [ In reply to ]
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power2max wrote:
Dear all,
Regarding our distribution that Ray mentions: check our website this coming Monday, things are moving and there will be interesting news for you guys in the States. Not saying more for now :-).
Cheers
Nicolas

Love ya Michael but this ^^^ will be great news!
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Re: Garmin Vectors Going Prime-Time [RChung] [ In reply to ]
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RChung wrote:
trail wrote:


I got a response from Stages:
[snip]

But he flat out says "do not affect." No mealy-mouthed claim there.


Cool. That's certainly unambiguous.

Yes, the claim is unambiguous.
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Re: Garmin Vectors Going Prime-Time [power2max] [ In reply to ]
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power2max wrote:
Hi all,

I am sorry that my response is not more in-depth, but unfortunately I am not at liberty to go into the technical bits because it always touches on the "how" and that is proprietary. As I said we have tested round and oval rings (Q and I got confirmation that Osymetric, too) against the Cyclus2 and there is no deviation when the oval rings are used.

Thanks for your understanding and happy training and racing,

Hmmm...I'm not that familiar with a Cyclus2 erg, but what sort of inertia (i.e. "flywheel effect") does it have? The reason being that if you try to see the "non-round ring inflation" on a trainer without adequate inertia, it will be lessened, or not even present.

That's why I did my testing on a LeMond Revolution (which has the equivalent inertia of an ~94 lb rider) and then also outside in conjunction with a PT wheel: http://bikeblather.blogspot.com/...ose-funky-rings.html

http://bikeblather.blogspot.com/
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Re: Garmin Vectors Going Prime-Time [Watt Matters] [ In reply to ]
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Watt Matters wrote:
Yes, the claim is unambiguous.

Well, how's this for backing up their claim with in-the-field, end user real comparison data: I had a brand new P2M mounted to Rotor 52/36 ROUND chain rings on my P5, and did a head-to-head comparison across my power range with my CompuTrainer as the control. The P2M matched the power curve of my CT to a tee, with the only exception being the P2M indicated about 10W higher across the board (which makes sense since the crank spider doesn't have friction losses to contend with). A few months later I modified my P5 with 52/36 Q-Rings using the same P2M, then ran the same tests. The resulting power curve was identical. Furthermore, the data on my head unit is just as stable with round rings as with Q-Rings. It doesn't get any more unambiguous than that. With a season of training and racing under my belt with the P2M, there has been nothing major to complain about when I think about what I paid for it. As long as it stays serviceable for as long as I expect to own it, then it was a great investment, and only time will tell in that regard.

Dave
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Re: Garmin Vectors Going Prime-Time [trail] [ In reply to ]
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trail wrote:


>Don't quote me on this...but my recollection is that it does.

I got a response from Stages:

"Oval rings or odd shaped rings for that matter do not affect the power reading. Since we use an accelerometer in our power meter that determines the position of the crank itself so the power meter reading would not be effected. Let me know if you have any other questions."


This is slightly vague - like the Power2Max guy - but I take it to mean that they sample velocity at a higher rate than once per revolution (presumably a significantly higher rate), which is certainly possible with an accelerometer.

But he flat out says "do not affect." No mealy-mouthed claim there.

Ummm...ok...I have some info here telling me that they sample torque over a pedal revolution and only calculate power once per crank cycle (which would imply a constant angular velocity assumption) and then transmit at 4 Hz (updated on the "events", just like Quarq).

So, until shown otherwise, I'll just chalk it up to another case of a PM representative not fully understanding the issue...oh well...

http://bikeblather.blogspot.com/
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Re: Garmin Vectors Going Prime-Time [Tom A.] [ In reply to ]
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>Ummm...ok...I have some info here telling me that they sample torque over a pedal revolution and only calculate power once per crank cycle (which would imply a constant angular velocity

Could be. But then again you "having some info here" is slightly less convincing to me! I laid out the problem pretty clearly to the rep, and he responded pretty unambiguously, so I'm rolling with it, so to speak, until demonstrated otherwise.
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Re: Garmin Vectors Going Prime-Time [djmercer] [ In reply to ]
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djmercer wrote:
Watt Matters wrote:
Yes, the claim is unambiguous.


Well, how's this for backing up their claim with in-the-field, end user real comparison data: I had a brand new P2M mounted to Rotor 52/36 ROUND chain rings on my P5, and did a head-to-head comparison across my power range with my CompuTrainer as the control. The P2M matched the power curve of my CT to a tee, with the only exception being the P2M indicated about 10W higher across the board (which makes sense since the crank spider doesn't have friction losses to contend with). A few months later I modified my P5 with 52/36 Q-Rings using the same P2M, then ran the same tests. The resulting power curve was identical. Furthermore, the data on my head unit is just as stable with round rings as with Q-Rings. It doesn't get any more unambiguous than that. With a season of training and racing under my belt with the P2M, there has been nothing major to complain about when I think about what I paid for it. As long as it stays serviceable for as long as I expect to own it, then it was a great investment, and only time will tell in that regard.

Dave

Was this a standard Computrainer? The CT is a relatively low inertia trainer. That's why Racermate also makes the Velotron, which has a humongous (that's a technical term) flywheel. The effect we're talking about isn't going to be easily spotted on a low inertia trainer, but you can see it on the road where inertia is high.
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Re: Garmin Vectors Going Prime-Time [trail] [ In reply to ]
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trail wrote:
>Ummm...ok...I have some info here telling me that they sample torque over a pedal revolution and only calculate power once per crank cycle (which would imply a constant angular velocity

Could be. But then again you "having some info here" is slightly less convincing to me! I laid out the problem pretty clearly to the rep, and he responded pretty unambiguously, so I'm rolling with it, so to speak, until demonstrated otherwise.

I can only say that it is info coming from someone intimately familiar with the calculation algorithm...

http://bikeblather.blogspot.com/
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Re: Garmin Vectors Going Prime-Time [djmercer] [ In reply to ]
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djmercer wrote:
Watt Matters wrote:
Yes, the claim is unambiguous.


Well, how's this for backing up their claim with in-the-field, end user real comparison data: I had a brand new P2M mounted to Rotor 52/36 ROUND chain rings on my P5, and did a head-to-head comparison across my power range with my CompuTrainer as the control. The P2M matched the power curve of my CT to a tee, with the only exception being the P2M indicated about 10W higher across the board (which makes sense since the crank spider doesn't have friction losses to contend with). A few months later I modified my P5 with 52/36 Q-Rings using the same P2M, then ran the same tests. The resulting power curve was identical. Furthermore, the data on my head unit is just as stable with round rings as with Q-Rings. It doesn't get any more unambiguous than that. With a season of training and racing under my belt with the P2M, there has been nothing major to complain about when I think about what I paid for it. As long as it stays serviceable for as long as I expect to own it, then it was a great investment, and only time will tell in that regard.

Dave

The claim I was referring to was the one by Stages, not P2M. But in any case your experiment doesn't resolve the question at hand with respect to measurement of crank rotational velocity.

Head unit display stability isn't relevent to the question.
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Re: Garmin Vectors Going Prime-Time [RChung] [ In reply to ]
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Well, to be fair, I did test an Osymetric ring on a CT and DID see the inflation on a Quarq. CT claims that they do some sort of manipulation with the load within a pedal stroke to"mimic"the inertial effects, and the fact that I saw the inflation, along with the pedal feel (it's actually pretty good) I'd have to say there just might be something to CT's claim.

Then again, I'm thinking the comparison of the P2M on a CT described above wasn't exactly rigorous. It is better to mount a round and non-round ring on the same crank and then switch back and forth while in erg mode...which is how I compared them.

http://bikeblather.blogspot.com/
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Re: Garmin Vectors Going Prime-Time [Tom A.] [ In reply to ]
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That's interesting. That would be a pretty responsive load generator. My only experience with a CT in ergo mode was before I had a power meter so I defer to your experience but I would have thought it would be easier to see a difference in trainer mode rather than ergo mode.
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Re: Garmin Vectors Going Prime-Time [RChung] [ In reply to ]
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RChung wrote:
That's interesting. That would be a pretty responsive load generator. My only experience with a CT in ergo mode was before I had a power meter so I defer to your experience but I would have thought it would be easier to see a difference in trainer mode rather than ergo mode.
The "pedal feel" on a CT definitely varies depending on the mode. I don't use ERG mode much, rather I vary between %FTP mode and course (simulated gradient) mode. It's more silky to ride in %FTP mode.

I don't know how frequently the load controller adjusts, but data samples used to be available for viewing at ~ 20Hz IIRC from the old software, although I haven't bothered with the old software for quite some time. Something enables them to provide a spin scan number for each of 24 sectors.
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Re: Garmin Vectors Going Prime-Time [RChung] [ In reply to ]
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RChung wrote:
Was this a standard Computrainer? The CT is a relatively low inertia trainer. That's why Racermate also makes the Velotron, which has a humongous (that's a technical term) flywheel. The effect we're talking about isn't going to be easily spotted on a low inertia trainer, but you can see it on the road where inertia is high.


Robert, it is a CT Pro.

For Robert, Watt Matters and other über techies: I think we need to differentiate the people such as yourselves who are capable of spotting an nth Watt difference here and there for purposes beyond simply riding a race with an even effort. For that, all your concerns and efforts to get the minutiae of each newer PM, be it Stages, Vector or the P2M are infinitely appreciated but beyond the scope of the 99th percentile and under. When the thread started to screech through a side alley, I chimed in with the reality check about end-user functionality with the P2M with round vs. oval, because for the purposes of hitting the road, the data is good (enough) and the manufacturer's claim appears to be valid. Anyhow, as fellow pocket protector sporter who loves the details, carry on......!

Edit: Apologies Watt M. I thought you were referring to P2M rather than Stages. No matter. The comment about head stability was due to my interpretation that there would be an indication about the unstable rotational velocity reflected in the head unit if it were so. My mistake as obviously I was wrong!

Dave
Last edited by: djmercer: Aug 20, 13 6:45
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Re: Garmin Vectors Going Prime-Time [djmercer] [ In reply to ]
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djmercer wrote:
For Robert, Watt Matters and other über techies: I think we need to differentiate the people such as yourselves who are capable of spotting an nth Watt difference here and there for purposes beyond simply riding a race with an even effort. For that, all your concerns and efforts to get the minutiae of each newer PM, be it Stages, Vector or the P2M are infinitely appreciated but beyond the scope of the 99th percentile and under. When the thread started to screech through a side alley, I chimed in with the reality check about end-user functionality with the P2M with round vs. oval, because for the purposes of hitting the road, the data is good (enough) and the manufacturer's claim appears to be valid. Anyhow, as fellow pocket protector sporter who loves the details, carry on......!

Dave:

You're right, of course, that not everyone cares about this sort of thing (or needs to, or should) -- it's probably a sign that they have a life. OTOH, I actually think that we all end up with better products cuz guys with insomnia and high boredom thresholds ask questions about how things work.
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Re: Garmin Vectors Going Prime-Time [RChung] [ In reply to ]
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100% valid. Both are signs of an exceptional mind, working full throttle all the time. Frankly, I'm exhausted just imagining the time folks like you pour into your intuitions, hunches and theories to turn them into validated white paper. I am truly an envious, appreciative fan.

Cheers---
DM
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Re: Garmin Vectors Going Prime-Time [djmercer] [ In reply to ]
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djmercer wrote:
Edit: Apologies Watt M.

Thanks but an apology was not necessary. It's all a bit of fun and yes the basic power stuff that most use is not overly demanding on high precision/accuracy.

The quest to understand the minutiae however does have its applications, so we keep trying to tease out what info we can, and will always seek to test and validate claims. Indeed, it's this sort of approach that has added extra arrows one can select to use from a power meter quiver.
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Re: Garmin Vectors Going Prime-Time [RChung] [ In reply to ]
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RChung wrote:
That's interesting. That would be a pretty responsive load generator. My only experience with a CT in ergo mode was before I had a power meter so I defer to your experience but I would have thought it would be easier to see a difference in trainer mode rather than ergo mode.

Well...I not only did the erg mode tests, but I also did a flat course 1 km TT in each ring (as you might have guessed, I was trying to see if the CT was "fooled" somehow in a test similar to what was done in the O'Hara study that Rotor quotes ;-)

Anyway...in both cases, erg and "free", I was struck by the smoothness of the rear wheel sound on the roller and load generator even WITH the Osymetric ring. The flywheel on a CT is so tiny it really looks like it's just on there for show, so I have to say it must be something they're doing in the control algorithm of the load generator. I was impressed...

http://bikeblather.blogspot.com/
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Re: Garmin Vectors Going Prime-Time [djmercer] [ In reply to ]
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djmercer wrote:
RChung wrote:
Was this a standard Computrainer? The CT is a relatively low inertia trainer. That's why Racermate also makes the Velotron, which has a humongous (that's a technical term) flywheel. The effect we're talking about isn't going to be easily spotted on a low inertia trainer, but you can see it on the road where inertia is high.


Robert, it is a CT Pro.

For Robert, Watt Matters and other über techies: I think we need to differentiate the people such as yourselves who are capable of spotting an nth Watt difference here and there for purposes beyond simply riding a race with an even effort. For that, all your concerns and efforts to get the minutiae of each newer PM, be it Stages, Vector or the P2M are infinitely appreciated but beyond the scope of the 99th percentile and under. When the thread started to screech through a side alley, I chimed in with the reality check about end-user functionality with the P2M with round vs. oval, because for the purposes of hitting the road, the data is good (enough) and the manufacturer's claim appears to be valid. Anyhow, as fellow pocket protector sporter who loves the details, carry on......!

Edit: Apologies Watt M. I thought you were referring to P2M rather than Stages. No matter. The comment about head stability was due to my interpretation that there would be an indication about the unstable rotational velocity reflected in the head unit if it were so. My mistake as obviously I was wrong!

Dave

Well...let's put this in perspective then...with the exception of Quarq (who admitted it would be an issue when asked up front), a representative from basically EVERY PM manufacturer that could potentially suffer from the "non-round ring inflation factor" has initially stated that using the those rings on their product would not affect the power readings...only to be shown later to be mistaken.

So...until shown otherwise (I'm sorry, but your anecdote doesn't qualify) or P2M decides to tell us the answer to the simple (and non-proprietary) question "Do you assume constant crank angular velocity within a pedal stroke when making your power calculation? i.e. is your power calculation "event based?" the prudent thing to do would be to assume that they too don't fully understand the issue.

It's not a tiny issue we're discussing either...for a ring with the ovality of the Osymetric, we're talking about a 4% inflation of the power level. At an FTP of 250W, that's a 10W error. If you don't think you need better accuracy than that, then save your money and get a PowerCal instead. Or, just train and pace with an inexpensive HR monitor. Why bother with the expense and compromises (for some) of a power meter?

http://bikeblather.blogspot.com/
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Re: Garmin Vectors Going Prime-Time [Big-Pete] [ In reply to ]
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The first firmware update for the Vectors was released yesterday.

Changes made from version 2.00 to 2.10:

  • Fixed a condition where Vector may not report power or cadence for up to four minutes after performing a static calibration.


https://forums.garmin.com/...rmation&p=209582

So far, I have to say, I've found the Vector pedals to be un-Garminly stable and reliable. I have no real complaints other than being eager for a Vector-aware 910XT firmware to simplify calibration.


@nugget: facebook - flickr - strava - runkeeper - garmin
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Re: Garmin Vectors Going Prime-Time [MacNugget] [ In reply to ]
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DC has put up his full review...

http://www.dcrainmaker.com/...n-vector-review.html

Also includes a link to his testing data.
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Re: Garmin Vectors Going Prime-Time [MacNugget] [ In reply to ]
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MacNugget wrote:
I have no real complaints other than being eager for a Vector-aware 910XT firmware to simplify calibration.


Thanks for the link, Sword. For what it's worth, I finally just broke down and bought an Edge 810 to supplement my 910XT. Adding the power meter left me dissatisfied with only having four data field displays to work with.


@nugget: facebook - flickr - strava - runkeeper - garmin
Last edited by: MacNugget: Sep 13, 13 8:16
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Re: Garmin Vectors Going Prime-Time [MacNugget] [ In reply to ]
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My LBS just told me that the Vectors are unavailable October. I'll wait and get them from my LBS just wondering if you all know if other retailers have them in stock?
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Re: Garmin Vectors Going Prime-Time [Lederman] [ In reply to ]
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I have a brand new pair at my retail store in Kirkland, Wa.
425-821-4301.
Ordered them for a customer but now does not want them. Sending them back to Garmin unless you want to purchase them.

Everyday Athlete
Kirkland, WA
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Re: Garmin Vectors Going Prime-Time [LanceCarter] [ In reply to ]
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I would love to but I have to stick with my LBS. I was just wondering if Garmin had sent out a big first shipment and now everybody was dealing with this unavailability. I'm sorry I can't take those off your hands. Thanks for the reply.
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Re: Garmin Vectors Going Prime-Time [Lederman] [ In reply to ]
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Lederman wrote:
My LBS just told me that the Vectors are unavailable October. I'll wait and get them from my LBS just wondering if you all know if other retailers have them in stock?

Not in stock, but I ordered a set from my LBS a couple weeks ago and they're expecting a shipment of them from Garmin next week. Fingers crossed.
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