BMW requires 4 wheel alignments to be accomplished by weighing down the vehicle with 50 lbs bags of sand. Each bag is placed in a specific location in the vehicle. A 330 would be different from a Z3 or a X5.
The real reason for using weights during alignment according to Dinan is to simulate the angles in the suspension when the car is driving at highway speeds. When you drive faster, you notice the car sits down lower and closer to the road.
As the car sits lower the wheels spread wider. This is caused by the aerodynamics of the car, the slant of the windscreen, slanted hood, underbelly, etc. BMW designed your car to sit lower when you drive faster, not to raise up and float.
The alignment specs are therefore there because BMW want specific numbers when you, the driver, need it most. This is when you are driving the car not when it is sitting in the parking lot at the shopping center.
At Peak Auto we use the most advanced Alignment machine made by HUNTER ENGINEERING called the Hawkeye. It uses extremely accurate cameras instead of the old fashioned laser technology.
Peak Auto is the only BMW service and repair center in Cary NC, Apex NC, and the Triangle area that performs this detailed service.