A vehicle frame that includes first and second frame portions. The first
frame portion has a plurality of struts associated with each other to
form a first framework. The second frame portion is associable with the
first frame portion in a stiffening association for significantly
increasing the stiffness of the first frame portion. The associated first
and second frame portions are configured to support a rider sitting on
the vehicle frame. The associated frame portions also define an interior
cavity dimension for housing a component of the propulsion system for
propelling the vehicle. The associated frame portions also comprise
attachments for supportedly connecting two wheels of the vehicle, a seat
disposed on the frame, and other vehicle accessories and systems.