[ScottBurson]

> Um, counter-rotating wheels are still gyroscopes.

Um, no. A system consisting of two identical wheels mounted on the same axle and spinning at the same speed in opposite directions has a total angular momentum of zero. It will behave like a solid object of the same mass.

[rwmj]

I'm still a bit confused about how a bicycle with counter-rotating wheels can move.

[chad_oliver]

The counter-rotating wheels are not the same as the two that the bicycle rolls on. So there's four wheels, two of which only exist to cancel the rotational inertia of the 'normal' wheels.

[pbhjpbhj]

This. However I wonder what it would be like to ride a bike on two rolling-roads so that the front and back wheels moved in opposite directions. Or, indeed, a trike/quad with large coaxial wheel separation and contra-rotating rolling-roads.

[usaar333]

The counter-rotating wheels probably don't touch the ground.