Abstract: A lift axle suspension system to be mounted under a vehicle for selectively raising and lowering a tire-wheel assembly into and out of engagement with a road surface which includes a beam mounted to a hanger bracket via a pivot connector. The hanger bracket is rigidly attached to a vehicle frame rail. An air bellows is interposed vertically between one end of the beam and the hanger bracket for lowering the tire-wheel assembly into engagement with the road surface and providing the support therefor. Another air bellows extends horizontally from the hanger bracket, and is pivotally attached to the beam by a pivot plate at its other end. The pivot plate is pivotally mounted to the beam such that expansion of said other air bellows will cause the beam to rotate about the pivot connector raising the beam and attached axle to raise the tire-wheel assembly out of engagement with the road surface.