Yesterday I hijacked a thread about pista crank length. While it was an interesting discussion, my real intent was to find out what the standard crank length was for road bikes over the years and why. From my recollection and perusing old catalogues on line, it appears that 6-1/2" (165mm) was standard on British bikes in the 1950s and 1960s. By the 1970s and 80s, 170mm looks like it was the norm. I can see one reason for the increase, people getting bigger, but were there other reasons or assumptions about what was ideal? Were 170mm cranks used in the 1950s and where? On larger frame bikes? In the mountain stages of road races? In continental Europe as opposed to Great Britain? Would 170mm cranks on a 1950s restoration be an anachronism?
John Betmanis
Woodstock, Ontario
Canada