Vehicle convertible from a tricycle two wheel drive to a four wheel four wheel drive

A vehicle of the tricycle wheel type in which transversely spaced apart wheels are located in the front of the vehicle and are rotatably driven to effect propulsion and steering of the vehicle, a caster wheel located generally centrally of the vehicle at the rear thereof, auxiliary wheels mounted on the rear of said vehicle and one spaced transversely outwardly on each side of said caster wheel, means moving said auxiliary wheels generally vertically relative to said vehicle so that they may be either spaced above the caster wheel or below the caster wheel, and means rotatably driving said auxiliary wheels thereupon optionally having a two wheel drive tricycle vehicle or a four wheel drive vehicle, said means moving said auxiliary wheels generally vertically including a cylinder and piston means for extending and/or retracting said auxiliary wheels, and means for generally vertically guiding said wheels comprising a generally vertically fixed square tube and a square piston-like member telescoped within the bottom of said square tube.