I've seen a lot of questions about disc brakes vs drum brakes, but until today I hadn't seen any actual data about the heat capacity of any of them. Velonews has an article about the new Magura hydraulic disc brakes, and they are tested to a fairly rigorous standard. Two cycles of absorbing 800 watts for 15 minutes, with a two minute cool off in between each cycle. That's claimed to be the equivelant of a single bike descending a 15% grade (for 15 minutes!! twice!!).
Does anyone have hard numbers for drum brakes or any mechanical discs?