At 01:58 AM 07/05/2008 -0700, Thomas wrote:
>I've often thought that crank length ought to have something to do with
>foot length more than with leg length (tho leg length ought to be part
>of the issue).
For simplicity, assuming all humans are proportioned the same (which obviously isn't the case), every part of a bicycle should be proportioned to the rider's height, including the wheels (which is also impossible). Even the wheelbase ought to be proportional, but we all know that is actually determined more by how the bike will be used.
Most British bikes in the 1950s had 6-1/2" (165mm) cranks. In the 1970s and '80s most cranks were 170mm, although a 21" Nishiki Landau I purchased came with 165mm cranks. In the mid 1980s 175mm aftermarket cranks became popular in America, presumably because people were getting bigger.
But getting back to Eddy Merckx' cranks. Although this is a track bike we're looking at, it was for the hour record, not for weaving up and down the banking while riding a Madison, so the customary 165mm pista cranks were not necessary. Although the bike specs someone posted from Wool Jersey said the cranks were 175mm, someone else observed that those in the photo posted looked "really long". I actually tried to calculate the length from the picture on my screen, presuming a 52 tooth chainwheel (which is what it looked like and that's also in the specs) and came up with 190mm. That seemed a bit long and I should probably have another go at it, but I would not be surprised if the cranks were actually longer that 175mm, given Eddy's size.