Self-levelling suspension

Self-levelling refers to an automobile suspension system that maintains a constant ride height of the vehicle above the road, regardless of load.

[1] This change in attitude affects aerodynamic properties, headlight aim, braking, bumpers, shock absorption from the suspension and the vehicle's performance in a collision.

Up until 1995 when they added "antisink" to the range when the engine was turned off, the suspension slowly lost pressure until the car rested on the bump stops.

If these were kept soft to maintain comfort they would compress too much under a heavy payload, restricting axle travel when off-road and compromising handling.

Land Rover developed a self-levelling rear suspension using the "Boge Hydromat" self-energising hydraulic strut.

[13] Of similar construction to a hydraulic shock absorber the strut used the motion of the suspension travelling over bumps to pump itself back up to a pre-set height.

In the 1990s Land Rover, in pursuit of the same blend of on- and off-road ability, developed an air suspension system that was both self-levelling and height adjustable.

BMW, Ford, GMC, Jaguar, Mercedes-Benz, Scania AB, Subaru and Volvo have each pursued numerous avenues to address this issue, including air suspension and rear axle mechanical devices.