Abstract: A vehicle with a chassis, a rigid axle carrying steerable wheels, a steering box or idler unit mounted on the chassis and connected by a linkage to the steerable wheels, wherein the steering box is pivotally mounted on the chassis about a horizontal fore and aft axis, and there is a compensating link connecting the axle and the steering box. When relative movement between the axle and chassis occurs, any component of such movement which could otherwise produce an undesired steering movement of the wheels, the steering box is caused to pivot by the compensating link so that no undesired steering movement of the wheels occurs.