Time trail bike question

I don't know a lot about bike frames, but I'll tell you what I do know.

The reason that road races don't typically have those solid rear wheels is rather simple: wind. A crosswind could easily knock down a bike with a rear wheel. Since road races are typically longer than time trials (3+ hours as opposed to ~1 hour), they aren't used. Also, rear solid wheels are a bit heavier than ordinary, so it theoretically isn't as beneficial to have one on during a race.

TT bikes are obviously different in their frame geometry. I believe, although I am not sure, that they are built especially for speed/aerodynamics, at a greater sacrifice of comfort.

very simple; it's forbidden in road races.

Quoted post said:

Originally posted by marlon1
very simple; it's forbidden in road races.

I don't have a UCI handbook with me, so I'm not arguing with you - I'm just curious. Are you sure?

After all, the opposite isn't too uncommon. Depending on the nature of the route, or the conditions, or the team's contracts, you'll see pros riding road rigs in TT events from time to time.

And many TT-dedicated rigs aren't too dramatically different from road bikes in terms of geometry -- some are, but I'm not sure they necessarily fall outside of UCI specs for standard road events. Or do they?

I know there are also regulations for how broadly aero certain frame aspects can be -- stuff like caps on fork-blade depth. But aren't those regulations enforced across the board? Are there really any forks that are TT legal, and not road legal?

On the other hand, there's definitely practical reason to avoid using standard TT rigs in road events -- some of which keydates pointed out. The sort of forward-dumping geometry favored by TT designs isn't going to be terribly comfortable or efficient on a standard large-scale road race, or a tight crit either. Handling could be screwy too. And few serious TT-bikes put the same kind of emphasis on lower-weight that top-end road frames posses.

Anyways, just curious. You could be right, Marlon, but the logic seems a little short. Of course, no one ever accused the UCI of being logical...

At the road world champs in Belgium Jeanie Longo used her TT bike in the road race (with Road bars of course).

Discs are commonly used in mass start races on velodromes. So I'm not sure if they are forbidden on the road.

Quoted post said:

Originally posted by tafi
At the road world champs in Belgium Jeanie Longo used her TT bike in the road race (with Road bars of course).

Discs are commonly used in mass start races on velodromes. So I'm not sure if they are forbidden on the road.

I rememebr roberto Gaggiolli using a disc wheel at the US PRo criterium champs once in the 90s....100km on a rear disc....ouch.

It would be like the old 100km TTT days at major champs.