Originally Posted by prathmann

I think you meant to write that it's the radius of the wheel that drops out of the energy equation - the mass definitely stays in. And tends to be smaller if the wheels are smaller with the same type of construction. While I agree that the wheel mass is such a small part of the total that it doesn't affect the overall speed or acceleration much, it's a part that is felt quite easily by the rider when starting up and the bike is being tilted from side-to-side and also steered back and forth a bit. So there's a different feel to a bike with light wheels.