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How long before the UCI ban this then ?
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https://www.cyclingweekly.com/...olympic-games-441456

Specialized have gone this way with the front fork on the Shiv.
But uber wide rear seat stays is new.
How do they meet the UCI 3:1 ratio at the top ?
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Re: How long before the UCI ban this then ? [BobAjobb] [ In reply to ]
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Oof. I hope they're fast!

Weird thing is that despite the wild fork and stays, the main triangle looks like a 90's tri bike.
Last edited by: trail: Oct 30, 19 6:52
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Re: How long before the UCI ban this then ? [BobAjobb] [ In reply to ]
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I guess the concept is that the seat stays are shielded by the rider's legs?

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Re: How long before the UCI ban this then ? [BobAjobb] [ In reply to ]
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The 3:1 ratio rule was dropped a couple of years ago
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Re: How long before the UCI ban this then ? [BobAjobb] [ In reply to ]
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Bizarre. I love it. Excuse my ignorance but do UCI rules apply to the olympics? I would assume they aren't technically a governing body of the actual events.

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Re: How long before the UCI ban this then ? [realbdeal] [ In reply to ]
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realbdeal wrote:
Bizarre. I love it. Excuse my ignorance but do UCI rules apply to the olympics? I would assume they aren't technically a governing body of the actual events.

yes, they are a governing body of the events. UCI falls under the IOC umbrella...

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Re: How long before the UCI ban this then ? [JasoninHalifax] [ In reply to ]
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I'd say it's primarily to avoid unwanted interference between tube wakes at the junction between the seatstays and seatpost. They may also act to reduce wake losses due to the legs by helping control the leg wake.
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Re: How long before the UCI ban this then ? [BobAjobb] [ In reply to ]
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I assume its already UCI approved but I don't see how the seat stay junction meets the rules surrounding the tube 'joints' rule 1.3.020. The rule does have a vague exception for track and TT bikes but I don't think the seat tube/seat stay junction meets the current requirements.
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Re: How long before the UCI ban this then ? [BobAjobb] [ In reply to ]
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From Chris Boardman's book the original wide fork was the result of CAD. This looks like they've taken that idea further.
For the track guys stiffness is a top priority. The cervelo bikes has some issues with the torque some people can produce.
The original Katsanis designed frames lasted 10 years!! Who here has a carbon bike that lasted 10 years? Under those loads those frame were special
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Re: How long before the UCI ban this then ? [trail] [ In reply to ]
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trail wrote:
Oof. I hope they're fast!

Weird thing is that despite the wild fork and stays, the main triangle looks like a 90's tri bike.

Yeah. It's surprisingly like my old Planet X Stealth in the front triangle
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Re: How long before the UCI ban this then ? [scott8888] [ In reply to ]
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scott8888 wrote:
I assume its already UCI approved but I don't see how the seat stay junction meets the rules surrounding the tube 'joints' rule 1.3.020. The rule does have a vague exception for track and TT bikes but I don't think the seat tube/seat stay junction meets the current requirements.

In the clarification guide on page 17 it sets out the seat stay junction further, and that area isn't subject to minimum/maximum dimension constraints either (p19). Basically if you make the angle of the seat stays steep enough (which is done here by mounting them very high) then you can get nearly 8cm across the seat tube box in a horizontal plane by having the extreme tip of the seat stay box just touching the back of the seat tube box.

I've seen a "beam" bike which conforms to UCI regulations which was extremely cleverly done - it does have to go through the approval process though so too radical and it'll just get made illegal the year following/the next opportunity for a large scale rule change.

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Re: How long before the UCI ban this then ? [BobAjobb] [ In reply to ]
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https://www.slowtwitch.com/...w_traction_1044.html

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Re: How long before the UCI ban this then ? [awenborn] [ In reply to ]
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Kind of sort of:

Main Frame dimensions can be no less than 25mmcross section and 80mm depth.
Fork and stays can be no less than 10mm and 80mm depth.

This is what happens when this is taken advantage of.



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Re: How long before the UCI ban this then ? [Ai_1] [ In reply to ]
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Ai_1 wrote:
I'd say it's primarily to avoid unwanted interference between tube wakes at the junction between the seatstays and seatpost. They may also act to reduce wake losses due to the legs by helping control the leg wake.

Also eliminates interaction between wheels and stays/forks.



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Re: How long before the UCI ban this then ? [bluntandy] [ In reply to ]
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bluntandy wrote:
From Chris Boardman's book the original wide fork was the result of CAD. This looks like they've taken that idea further.

Do you mean CFD?

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For the track guys stiffness is a top priority. The cervelo bikes has some issues with the torque some people can produce.

I have hard that. Though I've also heard some elite endurance guys talk about frames that are too stiff. And match sprinters are in a whole other world in terms of torque. Hard to make everyone happy.
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Re: How long before the UCI ban this then ? [trail] [ In reply to ]
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Track is also much less concerned with performance at higher yaw angles, so putting the forks/legs/seatstays inline is probably a better bet than out on the road.

Also, trispokes and discs (popular on the track) have bigger interference issues than wire spokes. In tunnel testing you can actually see the disruption every time a trispoke blade passes through the fork.

Kudos to them for innovating.

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Re: How long before the UCI ban this then ? [BobAjobb] [ In reply to ]
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Behind the Scenes (ish) video. Some other angles. Looks like it's still in prototype form and will be cleaned up a bit.

https://www.youtube.com/watch?v=L4xOsO57zis

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Re: How long before the UCI ban this then ? [Warbird] [ In reply to ]
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If this is true (as Orbea and Dimond also claim), then how come a brand like cervelo is still using very tight crowns on the PX and P5d?
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Re: How long before the UCI ban this then ? [Ex-cyclist] [ In reply to ]
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Ex-cyclist wrote:
Kind of sort of:

Main Frame dimensions can be no less than 25mmcross section and 80mm depth.
Fork and stays can be no less than 10mm and 80mm depth.

This is what happens when this is taken advantage of.

I actually know the guy who designed it but he was full of “no comment” when I asked him some specifics yesterday, which is fair enough. Apparently it’ll be used by one endurance bunch rider at the Minsk World Cup (happening now), and then further rollout likely in Glasgow next week. Some other federations have voiced concerns about what would happen in the event of a crash and those seat stays, I’m sure they’re plenty stiff though.

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Re: How long before the UCI ban this then ? [JasoninHalifax] [ In reply to ]
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And also maybe the seat stay (quite large) stabilize the air flow behind the legs, creating a virtual aero shape "leg + seat stay"

Brilliantly ugly.

Probably working on the track only, as no wind yaw, indeed.
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Re: How long before the UCI ban this then ? [trail] [ In reply to ]
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trail wrote:
bluntandy wrote:
From Chris Boardman's book the original wide fork was the result of CAD. This looks like they've taken that idea further.

Do you mean CFD?

Yep you're right.
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Re: How long before the UCI ban this then ? [bluntandy] [ In reply to ]
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We learned this more than 20 years ago at Zipp and even developed a 120mm fork crown fork with vertical blades that worked well with trispokes.. it sits in the lobby of Zipp to this day and was the inspiration for the Dimond front end (done by a Zipp employee) and also shared with GB cycling after a discussion I had with Boardman at Eurobike following the release of the gen 1 super bike they did that had the super tight fork blades and stays.. those bikes had been done entirely in CFD followed by a little wind tunnel validation, but had missed some of the wattage to spin issues related to the super tight blades/stays. Notably the next gen GB bikes had much wider fork blades and worked much better with certain wheels.

This one, however, is clearly next level. I've asked for some details that I can share from those involved and haven't heard specifics yet, but my assumption would be that they figured that they might as well push this stuff out to the centerline of the legs if they were going to be 50-60mm away from the wheel surface anyway.

Mathematically I'm quite interested as this is a pretty significant increase in A over most any other option, so the corresponding reduction in Cd must be quite large to compensate. Also interested in the continuation of right hand drive. There has been a lot of debate about the left hand drive concept and the data collection and means to get to those numbers. I know that this group had way more than enough money and capability to thoroughly investigate that as an option, so interesting to see that not being a feature here.

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Re: How long before the UCI ban this then ? [joshatsilca] [ In reply to ]
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Could it be that it is a reduction in rider-on-bike A?
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Re: How long before the UCI ban this then ? [Ex-cyclist] [ In reply to ]
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Ex-cyclist wrote:
Ai_1 wrote:
I'd say it's primarily to avoid unwanted interference between tube wakes at the junction between the seatstays and seatpost. They may also act to reduce wake losses due to the legs by helping control the leg wake.

Also eliminates interaction between wheels and stays/forks.

I’ve always thought this was a smart approach. My Speed Concept seems to be relatively wheel/tire agnostic whereas a friend who’s taken his P5 to the tunnel a number of times and he swears there are significant differences. E.g. a Zipp 808 with a 20mm SS is 5 watts faster than a HED Jet 9+ with the same tire and, similarly, the 808/SS is 5 watts faster than an 808/GP4000 (and this is before CRR).
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Re: How long before the UCI ban this then ? [BobAjobb] [ In reply to ]
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Great Britain....for a tiny island on the edge of the Atlantic we sure make some neat stuff.
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