Abstract: A trailer load shifting device comprises a framework adapted to ride along a trailer and to which weights are engageable. The framework incorporates wheeled carriers which are retractable and extendable by actuation of air bags positioned between the framework and the wheeled carriers. When the wheeled carriers are retracted, the framework of the device rests upon frame members of the trailer and is engaged to the trailer framework by removable pins. When the pins have been removed, the air bags are filled, extending the wheeled carriers and simultaneously raising the framework off the trailer frame members. Then, upon light snubbing of the brakes of a slowly moving tractor engaged to the trailer, the device can be shfited fore or aft, as desired, by its inertia.