Posted by Traveler on November 02, 19100 at 12:37:33:
In Reply to: another not quite posted by Ben on November 02, 19100 at 11:06:46:
The other day I was trying to figure out WHY drum brakes fade and disks don't. What I concluded could be all wrong, but here's what I'm thinking:
It is the velocity of the friction material versus the metal it contacts. Drum brakes operate at maximum lever arm and therefore maximum velocity. This has to heat the surface much faster than than the disc which operates with an equivalent lever arm of about 80% of the disc diameter, thus lower average velocity. The hot surface will boil off material and form a gas layer that keeps the friction material off the drum.
Opinions on this or what is the correct reasonimg?