Originally Posted by jccaclimber

With all of this conversation about bead expansion, I wonder if the aluminum rim expands faster than the bead does anyways? As a bare material it certainly does, I'm just not sure what it does as a system given the spokes, and I don't really feel like putting it into APDL to find out.

IME a third brake wouldn't be a bad idea. If nothing else it's a handy backup in case one of the other two ever fails. I don't see a situation where used responsibly (IE, it's not a true drag brake like an Arai, and the stoker doesn't use it without coordination from the captain) that an extra rim brake would not be better than an equivalent disc brake bike without it.