I'm a relative newbie with a background in high-intensity weight training. I've done extensive research into sizing, and components pursuant to planning my own ride from the ground up. At the present, I own two Bianchis:
(1) 2001 Giro, 55cm, Mavic CXP21, Shimano 105
(2) 2001 EV2 XL, 55cm, Mavic Open Pro, Chorus
Other than the fact that the EV2 is an ultralightweight racing machine, both visually appear to have virtually identical geometry, and the seat positioning is the same (as per my adjustments).
I've noticed that despite the inherent differences in frame materials and weight (which are AFAIK the only significant differents), I can ride the Giro faster over longer distances than the EV2. Puzzled, I've scratched my head trying to determine why. The interesting thing here is that the only real geometric difference between the two is the fact that the EV2 has 172.5mm cranks, and the Giro has 175mm.
My inseam is 78.75cm (31"), which by most calculations equates to a 170cm crank. I find that I am extremely comfortable with the 175cm - more so than 172.5cm. My comfortable cadence at effort seems to average around 85-90rpm.
My hunch is that while optimum crank lengths scale somewhat with leg length, a stronger leg of the same length will probably prefer a longer crank length. This works in my mind because in a free weight squat, the stronger leg of the same length will be able to squat lower with the same weight, which means the stronger leg will be able to exert more torque over a greater angular range of motion. Naturally, I am comparing legs of two people of same proportions and spinning ability, where one comes from a weightlifting background (like myself).
I'd like to hear any relevant opinions as to my observations, as I cannot figure why else I am slower on the 'faster' bike, and more comfortable pedaling at effort on the 'slower' bike. Could the modest difference in crank length really make the difference?
???
(1) 2001 Giro, 55cm, Mavic CXP21, Shimano 105
(2) 2001 EV2 XL, 55cm, Mavic Open Pro, Chorus
Other than the fact that the EV2 is an ultralightweight racing machine, both visually appear to have virtually identical geometry, and the seat positioning is the same (as per my adjustments).
I've noticed that despite the inherent differences in frame materials and weight (which are AFAIK the only significant differents), I can ride the Giro faster over longer distances than the EV2. Puzzled, I've scratched my head trying to determine why. The interesting thing here is that the only real geometric difference between the two is the fact that the EV2 has 172.5mm cranks, and the Giro has 175mm.
My inseam is 78.75cm (31"), which by most calculations equates to a 170cm crank. I find that I am extremely comfortable with the 175cm - more so than 172.5cm. My comfortable cadence at effort seems to average around 85-90rpm.
My hunch is that while optimum crank lengths scale somewhat with leg length, a stronger leg of the same length will probably prefer a longer crank length. This works in my mind because in a free weight squat, the stronger leg of the same length will be able to squat lower with the same weight, which means the stronger leg will be able to exert more torque over a greater angular range of motion. Naturally, I am comparing legs of two people of same proportions and spinning ability, where one comes from a weightlifting background (like myself).
I'd like to hear any relevant opinions as to my observations, as I cannot figure why else I am slower on the 'faster' bike, and more comfortable pedaling at effort on the 'slower' bike. Could the modest difference in crank length really make the difference?
???