For larger sizes (I ride a 57 cm top tube length, and between 57 and 61 cm seat tube length, even though the latter is of no consequence), it depends on the bike's design whether there is toeclip overlap. For my 43 size shoes, I need at least 600 mm front-center (distance BB-front hub center) to avoid it, 610 mm with fenders.
As pointed out before, it isn't an issue in racing, except perhaps once a year on a very tight switchback at 18+% - otherwise, you simply don't turn the wheel far enough. But it is an issue when commuting, touring and otherwise riding in traffic. The French low-trail geometries (with lots of fork rake) usually avoided toeclip overlap even with fenders. The typical British high-trail geometries (with much less fork rake) often did have toeclip overlap, especially when set up with fenders.
Some feel toeclip overlap on a non-racing bike is a compromise worth making, others feel it should be avoided at least on larger frames.
Jan Heine, Seattle Editor/Publisher Vintage Bicycle Quarterly c/o Il Vecchio Bicycles 140 Lakeside Ave, Ste. C Seattle WA 98122 http://www.vintagebicyclepress.com
> OK - let's get more precise! :-D
>First, the UCI regulations stipulate a minimum of 54cm from the
>center of the BB to the center of the front axle:
> 1.3.016 The distance between the vertical passing
> through the lower bracket spindle and the front
> wheel spindle shall be between 54 cm minimum and
> 65 cm maximum).
>I _had_ to look because... beforehand, I had taken out the
>carpenter's squares, measured 6 bicycles, and found that the
>only one which could definitely comply with a 58cm
>specification was my 1969 Atala (which has a 54.5cm top tube
>and what appears to roughly be a 71 degree head angle.) My
>Richard Sachs _might_ just barely make 58cm but it's difficult
>to be precise with a built up bicycle. Anyway, it's a moot
>point because the regulations stipulate 54cm.
> Leg length (relative to my height) was something of a moot
>point because that simply dictates saddle height. Also, it's
>obvious that head angle and fork offset have a large affect on
>this business but I really wasn't equipped to get accurate
>measurements in that department, which is why I sort of ignored
>them in my earlier message.
> So let's go with this: my European cycling show size is
>between 41 and 42 (depending on the manufacturer), and I set my
>cleats so that the ball of the foot is centered on the pedal
>spindle. In the list below, I've listed the bikes with the
>BB-to-axle distance (center to center), the crank arm length
>and the degree of overlap I perceive:
> Waterford track - 54cm - 165mm - lots of overlap
> LeJeune track - 55cm - 165mm - lots of overlap
> Witcomb road fixed gear - 57cm - 165mm - moderate overlap
> Peugeot road - 57cm - 170mm - moderate overlap
> Sachs road - 57.5 to 58cm - 170mm - some overlap
> Atala road - 59cm - 170mm - slight overlap
>I've always ridden the Atala and the LeJeune with Christophe
>toe clips (Medium) and that might exaggerate the situation.
>The others have been ridden with both toe clips and Look
>pedals, but there was overlap either way. Finally, the Atala
>has 32mm tires, which also exaggerates the situation.
> I hope this helps those who are concerned about this facet
>of bicycle fit. Suffice it to say, every adult road, track or
>touring bike that I've owned had toe overlap. Even my 1964
>Armstrong did - that's how I knew it was a "real" bike! But
>note that these were all small bikes, so the distance between
>the BB and the front axle has always been on the short end of
> Best regards,
> Fred Rednor - 725806 cm west of Georgetown, Washington, DC
>--- Steve Leitgen <email@example.com> wrote:
>> If I recall my framebuilding classes correctly the UCI
>> requires a
>> minimum 58cm distance from the center of the BB to the center
>> of the
>> front axle. Short frames will have the same clearance just a
> > shallower
> > head angle. (and therefore a longer fork rake)
> > Steve Leitgen
> > La Crosse, WI
> > On Jan 9, 2006, at 7:16 PM, Fred Rafael Rednor wrote:
> > > 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.
>> > looks to me that head tube angles were always about 72
>> > (perhaps 73 on my LeJeune tandem and maybe 74 on the track
>> > bikes.)
>> > 3) In general, this has never been a problem, although I
>> > not ridden with cranks longer than 170mm on a reagular
>> > 4) Here are the moments when it has been a slight
>> > inconvenience:
>> > a) Hollands frame with 52cm top tube (170mm cranks): you
>> > to keep your wits about you (and "time" your strokes) on
>> > 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
>> > wheel. So I lift the rear, and rotate the cranks a few
>> > 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
>> > issue at all. Even if he had some frames with short top
>> > 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?
>> > Cheers,
>> > 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
>> >> vogue?
>> >> 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?
>> >> Emanuel
>> >> =09
>> >> =09
>> >> =09
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