Originally Posted by
elcruxio
Also since the heavier wheel maintains speed better it'd likely be less fatiguing.
Yes, the higher inertia wheel decelerates more slowly than a low inertia wheel. But it also accelerates more slowly, which is where the muscle fatigue question arises.
Expanding what I wrote above, pedaling the high inertia wheel is like throwing a heavy ball a short distance, pedaling the low inertia wheel is like throwing a light ball a longer distance, and while the work done is identical, it's not at all clear which one is more fatiguing (or if they're equally fatiguing).