Quote: Maximize safe load-carrying capacity, increase stability and improve ride quality,Keep your TV level when you are hauling a heavy load,Improve steering control and braking when you are hauling or towing,Level your headlight beams, Reduce tire wear, Maintain even load distribution with air pressure, leveling off-center loads Air bags adjust manually, side to side, with individual inflation valves
Reduce strain on rear suspension. Prevent permanent sagging and excessive friction in leaf springs, Increase stability, Absorb road shock for a smooth ride, Soften contact between axle and frame to prevent bottoming out
X2 Good sensible commentary from BigD2