[MrForbes]

Hmmmm.....I dont' know whether or not you would have more ramming energy with more speed and less flywheel inertia, or the other way around, or the same. Interesting question.

Let's say you have two robots, Robot A has normal unmodified gearboxes. Robot B has gearboxes with very lightweight gears in them, so they can "spin up" faster given the same motor torque as Robot A.

Robot B would win a drag race, that is it would accelerate more quickly. However, Robot A would win a "coasting" race, as that extra energy stored in the heavier rotating gears would keep it moving longer than Robot B, after you turn off power to the motors.