A suspension system for a motorcycle, including a motorcycle mainframe, a swing arm pivotally mounted to the motorcycle main frame about a pivot axis, and an air bag suspension unit. The air bag suspension unit includes at least one air bag constructed of an elastomeric material. Without tools, the rider can adjust the air pressure in the air bags while operating the motorcycle by use of a power switch operably connected to a small compressor mounted on the motorcycle. The air bag(s) are housed within a slidable housing and which is mounted at one end to the slidable housing and its other end to mounting brackets on the motorcycle main frame. The housing is attached at its front end to the motorcycle main frame and at its back end to the swing arm. The housing also includes slide rods fixed to its forward end which slide within a pair of bushings. One alternative embodiment incorporates a conventional shock absorber along with the air bags to improve the handling of the motorcycle on rough or uneven terrain. A second alternative embodiment incorporates hydraulic mounts and self-contained range-of motion limiters.