Manny, (please forgive me if I'm being overly familiar),
Here's my experience as a relatively long legged short guy on 51cm to 53cm frames: 1) I have NEVER ridden a lightweight frame for 700c or 27" wheels that did not have some toe (clip) overlap. 2) The top tube lengths varied from 52cm to almost 55cm. It looks to me that head tube angles were always about 72 degrees (perhaps 73 on my LeJeune tandem and maybe 74 on the track bikes.) 3) In general, this has never been a problem, although I have not ridden with cranks longer than 170mm on a reagular basis. 4) Here are the moments when it has been a slight inconvenience:
a) Hollands frame with 52cm top tube (170mm cranks): you need to keep your wits about you (and "time" your strokes) on _very_ tight turns at _very_ slow speeds.
b) Witcomb fixed gear with 53cm top tube (165mm cranks): similar to above; and also at a dead stop (say at a traffic signal) my leading foot can hit the tire if I have to turn the wheel. So I lift the rear, and rotate the cranks a few degrees and then turn the wheel.
That's it - no problems, otherwise. As for Merckx... He rode much larger frames so overlap might never have been an issue at all. Even if he had some frames with short top tubes, he probably never was going slowly enough for it to be a problem.
What about Luison Bobet, a short guy who rode with long cranks? Perhaps in his case it was also never a problem because he never was going that slowly?
Fred Rednor - Arlington, Virginia (USA)
> How common was this on on-topic bikes, especially in
> the mid- to late 70s when short wheelbases became in
> Is it a problem in real riding conditions?
> I have 172.5mm cranks on a bike and already there's
> noticeable overlap (toe can touch front tire when
> wheel is turned at a certain angle) and wonder if
> going to 175mm is asking for trouble.
> What did Merckx do, given he rode on 175mm cranks?