TT Frame on road bike setup, UCI legal?

alexie

Hi everyone! My first post!

My current road bike has a standard road frame geometry with seat tube angle of 73 degree's, it is a size 52 frame (center-to-center) which i think is right for my height, i am 5'7 male. however i have a problem! i am unable to get into a neutral knee position! no matter how forward i move my saddle my knee still lies posterior to the pedal axial, even with the saddle forward at its maximum my knee remains posterior by approx 2cm.

To my amazement after some internet research i found that some people do have this problem which is related to the difference in thigh to lower led length difference which normally is a ratio of 1.3 to 1 (thigh to lower leg). It appears i am one of those with a longer lower leg, hence my inability to reach a neutral knee position over the pedals.

It seems the solutions is to go for a frame with a steeper 75 degree + seat tube angle. This leads me on to my main question, i am thinking about purchasing a Cervelo P2C tt frame and using it on a road setup with road bars opposed to aero, but does anyone know if this is UCI legal for road racing??? I mean look at the tubes on that thing! esp the seat post!! but also i did see this interesting article on velonews of ivan dominguez from toyota racing team who's road bike has a TT frame. But im not sure of the exact rules on this as his bike sports less aggressive airfoil shapes then the P2C.

http://www.velonews.com/article/74975/
http://www.cervelo.com/bikes.aspx?bike=P2C2008

my main choice in this frame is profoundly because of the increase seat tube angle to 75 degree's, but also because im planning on having a go at triathlon/duathlon next season and also road racing !

Your input would be greatly appreciated.

Tom Butcher

Not exactly sure what the official rules are but I know a couple of triathletes who road race on quintana roo tri frames set up as road bikes - certainly in lower cat road racing you'd be OK. If you are concerned what about the soloist or cervelo dual aren't they road bikes you can convert to a steeper seat angle ?

nickwill

I think you might be best to go and see a good bike fitter to asses your position.
If you are in the North of England, Paul Hewitt in Leyland is very good. He stocks a huge variety of frames, including I think, Cervelo. Someone like that could save you from making an expensive mistake!

alexie

Thanks for the post!

I thought about the dual soloist team and carbon frames, first frames i looked at actualy with the reversible seat post which gives ever effective seat tube angle of 73 or 75 degree's, but the thing is i only need the latter seat tube angle and no need for 73 degree's.

The pro's of the p2c is that it is also dual 75 but also 78 degrees which gives me the flexibility for a more time trial position when i do make the transition to triathlon. So maybe i'll go for this frame.

But its good to know some triathletes are aloud to race low categories on modded TT/Road bikes. its looking hopeful

alexie

Nickwill thanks for the contact,

unfortunately im in London and am not will to make a long ass trip to get a bike fit. Could you advice anyone in south-east england if you know any?

Cheers

pete.whelan

go to a good bike shop, like Condors and get measured up. They will then be able to say if there are any off the peg frames from various manufacturers available or if you need a custom set-up

scherrit

Not every one believes in knee over pedal spindle (KOPS) as the be-all and end-all.... it's not too bad a place to start for most road positions, but some people land up being better off biomechanically further back or aerodynamically better off further forward. track sprinters often like their saddles so far forward (over the BB) that their bikes are technically illegal for massed start events....

The British cycling site has links I think or copies of the relevant rules.... I'd guess that a sound road position would not fall foul of the rules.... dunno about the bike frames, though... the cervelo people will know and they've been most helpful when I've emailed them.
Good luck,
Scherrit.
www.thebikewhisperer.co.uk

Monty Dog

Are you not confusing your KOPS position with the need to get the nose of the saddle 5cm behind the BB spindle centre? For racing in the UK the most critical aspect of scrutineering bikes is for the safety of the rider and the others in the race - there's too many other things to woory about on the day in race events than looking at everyone's bike position. I'd set your bike up whatever way you find suitable for you and get racing. In terms of getting a bike fit done, there's Sigma in Kingston or Cycles Dauphin at Boxhill, both are Cervelo dealers and could advise on position - if you buy the bike from them I'd expect to get the bike fit for free. Whilst a 78 degree seattube might be fine for Triathlon with aerobars, for road racing with drop bars, you could find it throws your weight too far forward and when corning hard, could cause the wheel to wash-out - road bike geometries have evolved based on experience and finding what works - they just didn't happen that way.

scherrit

Nope, my understanding was that the OP was trying to get to a kops psn but I was just bimbling on generally about uci rules vs a good position, and what I should have said, is what you said, specifically:"set your bike up whatever way you find suitable for you and get racing"
S.

aracer

Monty Dog wrote:

Whilst a 78 degree seattube might be fine for Triathlon with aerobars, for road racing with drop bars, you could find it throws your weight too far forward and when corning hard, could cause the wheel to wash-out - road bike geometries have evolved based on experience and finding what works - they just didn't happen that way.

Though the whole point of a bike designed with a 78 degree seat tube is that unlike putting a forward position seatpost on a normal frame they should have adjusted other bits of the geometry so that your weight is still centered. My TT frame (though only a 76 degree seat tube angle) certainly works that way. The use of drop bars rather than tri bars shouldn't really make a significant difference as the body position will still be the same - if anything you'll be a bit further back with the drops.