Originally Posted by
elcruxio
I wonder how a drum brake is able to withstand more prolonged drag braking than a properly specced disc brake. Drum brakes are enclosed so not much heat dissipation from the actually heating elements of the brake.
There are ways to make a disc brake more heat resistant and prevent pad glazing. Mechanic caliper, 203mm or even 220mm rotor, metallic pads and added rotor thickness (tektro makes a rotor that's 2.3mm thick. Standard is 1.6mm or 1.8mm)
But that’s not what the OP has built. Drum brakes in these applications have the advantage of much more mass and surface area to dissipate heat. They also have the advantage of much larger brake pad surface area. Santana made a disc based drag brake but it was over 250mm and Hope made one which was a vented design like in vehicles. Both were very specialized and had limited adoption in an already limited marketplace.