2 road cyclist vs 1 TT cyclist

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Alex Simmons/RST
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Re: 2 road cyclist vs 1 TT cyclist

Postby Alex Simmons/RST » Wed Oct 05, 2016 2:32 pm

DaveQB wrote:
Alex Simmons/RST wrote:Those non standard shaped bidons are not permitted in events run under UCI regulations in any case.


Really?
But this is ok?
https://goo.gl/images/LDVHcH
I use this ^ and saw it in use in the Vuelta (ITT) this year.

See my post above. If it fits the dimensions of the rule, it's OK. Quite a few were made that didn't, were really frame fairings masquerading as a bidon. Clever but they got the flick.

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Re: 2 road cyclist vs 1 TT cyclist

Postby g-boaf » Wed Oct 05, 2016 2:55 pm

DaveQB wrote:
Alex Simmons/RST wrote:Those non standard shaped bidons are not permitted in events run under UCI regulations in any case.


Really?
But this is ok?
https://goo.gl/images/LDVHcH
I use this ^ and saw it in use in the Vuelta (ITT) this year.


For exactly the reasons Alex mentioned, some of the bottles were made illegal.

Page 41 will give you more information:

http://www.uci.ch/mm/Document/News/Rule ... nglish.pdf

They've also cracked down on the hydration backpack type systems too, as those were becoming aero improvements, rather than devices to help with hydration...

CAMELBACK
Hydration is an essential physiological consideration for athletes during a physical effort. Neither bottles nor camelback systems should diverge from their original function. There is a significant risk of camelback systems or any similar devices being used for other purposes than their original function. For this reason certain restrictions apply if they are to be used in competition:
• The camelback system is authorised for competition solely for the purpose of rehydrating the rider
• It must not be the case that the system, presented as a way of improving a rider's hydration during an effort, is accompanied by a "aerodynamic clothing" advantage, in this way deflecting the camelback system from its original function.
• The liquid container must not be capable of holding more than 0.5 litres and must not be a rigid shape liable to be considered as a
device for improving the rider’s aerodynamic qualities.
• The use of the camelback system must not modify the rider's morphology and must thus be directly attached against the body
• It is recommended that this equipment should be presented to commissaires before the start of the event in order to avoid any risk of illegal use and disqualification.

Following many problems on the positioning of the camelback systems during the 2011 season, the UCI decided to take additional measures which came into force on 1 April
2012:
• The use of the camelback system is only allowed on the back of the rider
• It is mandatory for all riders who want to use a camelback system to present it to the commissaires before the start of the race at the risk of being disqualified.

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DaveQB
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Re: 2 road cyclist vs 1 TT cyclist

Postby DaveQB » Thu Oct 05, 2017 2:11 pm

Alex Simmons/RST wrote:I don't think it's a clear cut as some are suggesting. The aero differences between road and TT set ups can be sizeable.

For example, a 5% improvement in speed from road to TT bike at threshold power is not all that wild (certainly for me it's not), and for the pair on the road bikes that requires the rider in front to be putting out ~15% more power than the TT rider.

So if we assume the TT rider maintains 100% threshold power, then the road pair need to alternate between ~115% of threshold power when on the front to match the TT rider's speed and ~ 85% of threshold power when drafting, which is somewhat harder than averaging 100% of threshold in a quasi steady state, because the physiological cost or strain is not linear with power. Indeed there are some that couldn't manage that sort of power variability for long enough.

I'd say that if the speed differential at threshold power between the set ups is less than ~4%, then the roadies will take it, at 4-5% it's line ball, but if the aero differential results in >5% speed difference between the sets ups at threshold power, then the roadies will have a hard time beating the TT rider's time on course.


I was reminded of this thread the other day when I was also reminded that having someone draft off you, gives you a 5% improvement. I had forgotten that when I created this thread. So this would effect some of the maths. Probably just making it more complicated than need be with little impact on the result :)
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