Self-levelling suspension.

Keep on the level even when you're towing a heavy load: Self-levelling suspension adjusts the height of your vehicle's rear axle for better driving dynamics and safety.

Carrying heavy luggage or towing a trailer can cause a vehicle's tail to sink downwards. BMW's self-levelling suspension system counteracts with problematic tendency by inflating pneumatic cylinders integrated in the rear axle assembly that lift the chassis higher. Pneumatic pressure is maintained by auxiliary compressors which are electrically operated. The compressors run independently of the engine and can be adjusted individually if required - for example, when carrying an uneven load.
Maintaining a steady chassis level is essential to your BMW's dynamic handling. Towing or transporting heavy loads can lead to uneven tyre wear. Furthermore, oncoming drivers can be blinded by the upwardly-tilted headlight beam. BMW self-levelling suspension eliminates these dangers.