Originally Posted by tholub
If it's not you, it'll be someone else; our time trial records are going to be set on gears much bigger than 54", by someone who doesn't mind going 40+kph. Even now I'm pretty sure Chuck would only need a little bit of training to be comfortable pushing a 90" gear with 170mm cranks.
Having seen Sam ride a 36" Schlumpf, I think his 'top-out' cadence is alot higher than most.
For flat speed, the limiting factor currently is not gearing, it's the wheel. The 36" are still about three or four times heavier than an equivalent track bike wheel.
I can see a lightweight V-frame, very highly geared 28" on a smooth straight track hitting close to 40km/hr though.