A portable towing system for a motorcycle or similar vehicle, such as a trike, the frame of which can be lowered to ground level to facilitate loading of the motorcycle or similar vehicle by pushing or riding the vehicle onto the frame without risk of the vehicle falling off the sides of a steeply inclined ramp. The towing system may be assembled, raised, lowered, and disassembled by a single person, if desired. The raising and lowering of the frame is effected by a lifting and lowering mechanism connected with the wheel assemblies.