Chris, Pete, a disc wheel is designed to provide the most aerodynamic advantage possible for a bike. Aerodynamics trumps weight considerations unless the course you are riding has an extreme amount of climbing. Due to it's rotational energy, a disc can actually provide a good degree of stability in cross winds. However, if a steady or gust wind of say 30mph+ is predicted for a race, I would opt for a deep rim wheel over the disc, but that's pretty rare. The front wheel actually has more impact on bike handling in wind then the rear, that's why you will never see a bike with a front disc wheel. that would be un-rideable in any appreciable wind. At the Ironman World Championships in Kona, HI, they don't allow disc wheels at all due to high cross winds, although most of us athletes think it's an excessive response to the conditions there.
