BMW xDrive System

The BMW xDrive system was first introduced on the BMW X3 in 2003. The xDrive system uses a wet multi-plate clutch mounted on top of the front drive shaft output located inside the gearbox. This helps splitting power from the transmission system to the front and rear axles. BMW has set up the xDrive permanent four-wheel drive system to send 40% of the engine’s power to the front wheels and 60% of the power to the rear wheels. This helps retain a lot of the traditional BMW rear wheel drive feel. As a result BMW’s Sports Activity Vehicles (SAV) have great on-road drive dynamics which give them car like road manners. 

The xDrive system is connected to the vehicle’s on-board computer which also receives feedback from the vehicle’s Anti-lock Braking System and Dynamic Stability Control (DSC). The moment traction control system (in this case DSC) or ABS detects wheel slippage the wet multi-plate is activated by a servo motor to shift the torque from the wheel/s that are/is slipping to the wheel/s with more traction. This prevents the car from losing its composure as the driver does not lose control of the vehicle. The driver of the vehicle simply has to steer the vehicle in the direction he want’s to go in and the xDrive system shifts torque from wheel to wheel within milliseconds while deciding how much power to send to each wheel depending on the amount of traction it has. At the same time the DSC system applies just the right amount of braking at the wheel/s which lack/s traction so that the car continues to move in the required direction. 

This means that BMW’s equipped with the xDrive system can drive into a corner much too fast and the system will detect understeer and oversteer to apply the brakes via DSC system. Power from the engine is shifted from wheel to wheel to negate any hint of oversteer and understeer by slowing down the vehicle. The system works so fast the driver can barely feel any understeer or oversteer. The xDrive system uses an open differential design to allow the DSC system to apply the brakes on the wheel/s without traction while the on-board computer shifts power to the wheel/s with traction.