The motorcycle frame is made of high strength, lightweight, aircraft grade aluminum. At the tail end, they install the controller; the link between the battery and the throttle, which controls the electricity flow to the motor. They mount a suspension system … an aluminum swing arm that attached to the rear wheel on one end, and to the frame on the other, via a spring shaped shock absorber, which expands and contracts to dampen bounce as the wheel moves up and down over bumps in the road.