Originally Posted by
nz6666
Can't understand how do you get the same effort conclusion. For example, to get the same gear inches (hence same speed or distance per pedal stroke) on both bikes the small bike has to use a bigger chain ring and/or smaller rear cog due to the smaller diameter of the wheels. Any of these (bigger chain ring, smaller rear cog) translates to more effort right? It's like you are riding then suddenly switch to a higher gear (front or rear) then you must spend more effort.
NO, for two reasons:
1. A bigger chainring or smaller cog does not matter if the gear inches are the same. The larger chainwheel is only "harder" if you keep wheel size the same.
2. A higher gear is not necessarily "harder." It requires more pedal pressure but a smaller distance (fewer rev's) to do the same work. That may be more or less biodynamically efficient.