Abstract: Apparatus providing a pivot axis for rear wheels of a vehicle is disclosed. The vehicle has a chassis, an arm pivotally attached to the chassis and four rear wheels divided into two forward wheels and two rearward wheels. The apparatus of the present invention has two halves, wherein each half includes a rocking member and a ground directing member. The rocking member is pivotally attached to the arm at a central location on the rocking member and rotatably connected to one forward and one rearward wheel at front and back locations, respectively, of the rocking member. The ground directing unit is pivotally attached to the arm and to the rocking member near the rearward wheel. Accordingly, the ground directing unit provides a force to the rearward wheel while no force is provided to the forward wheel.