The weight of a truck, and thus the axle load, fluctuates greatly depending on the payload at any given moment. To meet the resulting suspension requirements, virtually all commercial vehicle manufacturers now employ air springs. In providing for level control, air springs also guarantee that the vehicle body maintains a constant road clearance. This, in turn, ensures safe driving regardless of the loading conditions. The vehicle body can also be raised or lowered by means of air springs actuated via optional auxiliary manual controls. This is of advantage in adjusting vehicle body height to the level of a ramp or in placing an interchangeable platform.
Air suspension on trailers ensures not only gentler treatment of the load being hauled but also less wear and tear on the roads. This aspect is of growing importance as traffic volume becomes increasing dense. As a rule, each axle has two air springs. In multi-axle combinations, one axle is frequently provided with an axle-lifting device to protect the tires on empty runs or when the vehicle is only partially loaded. Usually convoluted air springs are used for raising and lowering lift axles.
Cab & seat
Air suspension of the cab has a major impact on riding comfort. These air springs are sleeve-type rolling lobes and are arranged in a four-point suspension between the driver’s cab and the chassis frame.
Air spring seats provide a more ergonomic and comfortable working situation. This helps to ward off driver fatigue or health impairment.