Suspension; Air Suspension - BMW E61 Sports Wagon 530xiT Owner's Manual

Suspension

The E61 features an all-aluminium chassis as already introduced on the E60. A variant
of the integral link rear axle IV has been developed for the Touring that makes for a com-
pletely flat luggage compartment floor while providing a very large through-load space.
The 530xiT is equipped with an automatic self-levelling suspension provided by air sus-
pension at the rear axle as standard.

Air Suspension

The air spring installed in the E61 is similar in operation to the system installed in the
E65.
The advantages of an air spring on the rear axle can be felt particularly in vehicles with
high payload (such as a sport wagon) as mainly the axle load at the rear axle changes
when loading and unloading the car.
With a conventional steel spring, the change in the axle load affects not only the ride
height but also the vibration and suspension geometry.
There would also be a change in the camber of the rear axle wheels at high payload -
this would result in increased load at the inner shoulders of the tires which in turn would
mean reduced load bearing capacity of the tires.
The air springs and dampers are supported independently on the floor pan of the car
body.
Rear Air Suspension
6
E61 Sports Wagon