Originally Posted by livedarklions

That's not helpful at all. Assuming that the riders are approximately the same size (or this is now an aero question instead of a weight one), you now have a rider who's probably well below average in strength operating a bike made out of lead. At least when the riders were closer to each other in weight and size, there was some question as to differences in fitness levels. By going to extremes, I either have to assume that one of the riders is very heavy for his size or very light, both of which possibilities will affect the rider's ability. If anything, you've just demonstrated that we don't have enough information to answer the question--we need to know what kind of extra weight the heavier rider is carrying because leg muscle might improve performance.