A suspension system suspends an axle from a vehicle undercarriage. A mounting mounts a trailing arm for pivotal motion about a horizontal axis passing through a proximal end of the trailing arm perpendicular to the direction of vehicle travel while the vehicle is being steered in a straight line. An air spring is disposed between the undercarriage and a distal end of the trailing arm. A fastening holds fast together the middle of a resiliently flexible locating strap, the middle of the trailing arm, and the axle. A front locating bracket and a rear locating bracket fastened to the undercarriage respectively locate the front end of the locating strap horizontally in a direction parallel to the horizontal axis about which the trailing arm pivots and the rear end of the locating strap horizontally in a direction parallel to the horizontal axis about which the trailing arm pivots.