Originally Posted by
Carbonfiberboy
There is a difference, however. A light bike "gets out of the way" of a strong pedal stroke. It accelerates as the pedal force peaks, so that the peak force duration is relatively short. A very heavy bike, however, does not accelerate away from the pedal at the same cadence, so the high force duration lasts longer.
Sorry, not convinced. The "peak force duration" is by definition merely a function of your cadence, not of the weight of your bike. If I pedal at 100 rpm on a road bike my "peak force duration" is exactly the same as if I pedal at 100 rpm on my tourer with 50lbs of gear.
Your argument holds water only if you are reducing your cadence in response to the weight of the bike and thus turning the ride into more of a strength workout than an aerobic workout. This is quite likely, but you could achieve the same effect by simply moving up a few gears on the road bike.