Originally Posted by
Trakhak
That, and also wheel inertia. Plus, riding into a headwind, you have to re-accelerate the combined weight of you and the bike as each pedal passes through top and bottom dead center.
Sorry, by “crank inertia” I really meant “crank inertial load”, which combines all the effects of rider/bike mass and inertia along with gear ratio. The rotational inertia of the crank itself is trivial.