A pivot steering vehicle having a pair of hydrostatically operated driving wheels; and motors for driving those wheels which are driven by variable speed, reversible pumps; a control system is provided, having valve means for controlling the pressure applied to the pumps for controlling the speed and direction of the pumps; and cam means is provided which, in response to turning movements of the steering wheel, reduces the speed of the inside driving wheel, and after a predetermined point in the turning movements of the steering wheel, reverses the direction of that wheel.