prathmann, I'm fully with you on the calculation of F (drag force), but why would power depend on ground speed? When I think about power, it's driving the continual acceleration required to maintain speed against resistance (some rolling resistance and bearing drag, but mainly air resistance) which is trying to decelerate the rider. I'm not saying you're wrong (and your calculations are consistent with our experience), but theoretically, I still don't understand why ground speed is part of the multiplier for calculating power. Can you explain the rationale here a bit more?