Abstract: A bolt-on kit for converting conventional two-wheel motorcycles to three wheel form. The kit comprises an elongated axle assembly which is adapted to be coupled to the motorcycle and which receives the original equipment drive gear for rotation, a pair of spaced apart mounting plates coupled to the axle, support means for rigidly coupling the mounting plates to the motorcycle frame, a pair of drive hubs for mounting drive wheels at opposite ends of the axle assembly, and unique stabilizer means. The stabilizer includes a vertically, upwardly extending brace which is yieldably, slideably received within appropriate bearing structure to allow vertical suspension displacement while preventing damage to the motorcycle frame from torsional or twisting forces.