In its simplest form, it counteracts against an overloading of the boot (trunk). For this purpose it is integrated into the shock absorber or works as an additional air spring. Without a compressor, air must be pumped from outside and then be released again after unloading. Vice versa, the ground clearance can also be distinctly raised above the normal measure. In this case however, only a very low maximum speed is permissible. Recently, through the air suspension, even all-wheel-drive estate cars become 'almost-SUVs'.
The advantages of the air suspension sound tempting:Whether loaded or unloaded, the greatest possible comfort while driving is offered. Loading surface- and lighting height remains constant. At higher speeds the car body is lowered for aerodynamic reasons. Although there are still (possibly electronic) shock absorbers, the suspension can also be influenced in fractions of a second. As soon as the sensors note a too strong build up of see-sawing, a portion of the elastic air is closed off by a valve, thus reducing the volume. These measures are also possible when swaying in curves, diving when braking and front-end rising during hard acceleration occurs.
Nowadays, there are sensors which recognise poor road surfaces. To react automatically in this situation, is a question of expense and the fact that the electronics are slowly reaching their decisive limits. It degenerates almost into paternalism if the vehicle, even after receiving the various parameters over and over again, reverts to a certain ground clearance height. Even the manual vertical adjustment is bound by certain speed limits. Modern top-of-the-range motor cars and off-road vehicles, use the air suspension not only for the increased suspension comfort, but also associate it with driving safety and variable ground clearance. The suspension is, independent of the driving speed, hardened step-by-step and the vehicle is lowered, whereby, the attainable maximum speed can also increase distinctly. 10/09