Load-leveler suspensions maintain an optimum ride height when heavy cargo is loaded into the rear of a vehicle or when towing and hauling a trailer. In either case, the additional weight causes sagging suspension: the rear end sags and the front raises up … causing problems with handling, braking, and stability.
There are two main types of load leveling shocks. One is a hydro-pneumatic system that automatically pumps more fluid into the rear shock absorbers to maintain the right ride height, while still absorbing bumps. This is one of the best shocks for towing.
The other is an air-spring suspension — sometimes at all four corners — that automatically pumps air into “air bags” to raise the vehicle and compensate for a heavy payload or trailer. You can buy self-leveling rear shocks and air suspension products as aftermarket items. If you have to carry heavy loads and/or tow a heavy trailer, a load-leveling suspension can make your life easier and driving safer.