Quote:
Originally Posted by CurtEgerer
John - didn't see your Peugeot last night ... dang, I never would've sold that one!
On crank arm length, some of it is probably down to the individual rider's tolerance for geometry changes. Some of us can barely ride if the saddle height or cleat position is changed 2mm. Others? They can jump on anything and don't seem to notice. From a purely ergonomic standpoint, there is an ideal geometry for every rider (whether they like it or not  ). |
For modern, compact frame geometry makes it really easy but I do prefer a smaller tighter fit rather than going up in frame size.
For vintage bikes and within reason, I can accept a range of frame size. I'll swap stem's and sometimes a seat post and make it work. I also carry the needed wrench's during a ride and tweak adjustment. It takes a number of rides and I'll only raise the saddle in small increments. I don't make drastic adjustments.
Can understand how vintage bikes can be nitpicky for some. Stretched out (LeMond style) top tube is easier on the back, arguably more aero and the most comfortable for me. Although, riding a smaller vintage frame can crunch me, seems more like a modern bike, feels quicker in transition- fun sprinter and climber. Those smaller frames are more fun in shorter, faster club rides but for centuries or distance, I'll go for the stretch and flatter back. Just seems more comfortable. (Same when captain on the tandem.)
Crank length. I don't get the science of it either. The long arms worked well for high bottom brackets and mtn. bikes, but I'll stick with the 172.5 or less for road bikes. If I'm riding with the drop bars and low, my knees are just close enough without hitting the elbows.
And then there's another factor, at least for me. It depends on whether the bike has dual control or vintage old school downtube shifters. Weird eh? Dual control convenience makes keeping cadence ridiculous easy and keep the chain dancing.
On bikes with the old DT shifters, its fine with a close range set of cogs but for the wide ratio sets sometimes I don't always feel like constantly reaching down. I just leave it one gear and grunt it out. I know its all wrong but as long as I know my knees give me a pre- warning, use some pedal lift + push technique, can get away with a larger chainring on shorter crankarm's.