Downhill racing specific rim. The tube that goes from the fork to the crank. Same as the drive train on your car. The part of the frame and fork that the wheels are bolted into. Modeled after car brakes.
Brake pads push out against the drum, which is mounted on one side of the front and back wheels.
Greater braking power than traditional cantilever brakes and disc brakes, but heavier and more complex. Very effective braking system, but not as popular as the others due to complexity and expense. Heavier than any other braking system. Mainly popular among downhillers. The part of the fork that connects the steer tube to the fork blades.