I'm no engineer, but I imagine there would be substantial energy loss through the movement within the wheel. Not to mention lack of traction with the road. Loo

I'm no engineer, but I imagine there would be substantial energy loss through the movement within the wheel. Not to mention lack of traction with the road. Looks like another solution to a problem that doesn't exist. Bicycle wheels are light, cheap and can be adjusted easily by changing the air pressure.