Abstract: A steering controlling apparatus for an articulated truck-trailer combination, wherein the front and rear ends of the trailer have front and rear rotatable steering transmitting plates thereon which are joined together by a crossed cable arrangement so that rotation of the front plate causes a corresponding rotation of the rear plate in the opposite direction. The rear plate is coupled to the rear axle assembly to cause corresponding horizontal angular displacement thereof. The front steering transmitting plate is coupled to the rear coupling plate of the truck such that the front steering transmitting plate is rotated relative to the trailer whenever the truck is turned, at least up to a maximum angular extent, to cause corrective steering of the rear axle unit so that it will approximately trace and follow the same path as the truck when turning.