Jan wrote:
Your assertion that the European pro racers were concerned about the cranks breaking would make sense if they always used steel cranks. However, a number of pros (but of course, not all) used aluminum cranks on mountain stages, where riding out of the saddle and sustained high power outputs will stress the cranks most. (If you are going to break a crank, it will be in the mountains!)
Consider that switching cranks between stages also required switching the bottom bracket (square-taper vs. cottered). This was not a trivial thing to do. I believe the consistent use of aluminum cranks for the mountains and steel cranks for the flats cannot be explained with a fear of cranks breaking. I propose that the well-documented concern about tread width (Q factor) provides an explanation that is consistent with the observations.
As already raised by Marcus Hellman, given that you have apparently already done the research and it will therefore not require any new work for you, could you please list the pros who used the differing cranks along with the documentary proof. Could you also show that the same bike was used and the team mechanic switched the BB out overnight? Can you also document how you came to the conclusion that cranks break more frequently in the mountains? This seems counter-intuitive to what I have personally seen in races. Most breakage that I have witnessed occurs far away from the hills, besides which light weight is not historically claimed to be beneficial in flat stages anyhow, so what is the benefit of fitting alloy on the flats?
Steven Maasland
Moorestown, NJ
USA