Aldrich Accessories, A motorcycle frame is a motorcycle’s core structure. It supports the engine, provides the hinge points for both front and rear suspension, and supports the rider and any pillion or luggage. Also attached to the frame are the fuel tank and battery. At the front of the frame is found the head tube that holds the pivoting front fork, while at the rear there is a pivot point for the swingarm. Some motorcycles include the engine as a load-bearing stressed member; while some others bikes do not use a single frame, but instead have a front and a rear subframe attached to the engine.