What is BMW xDrive? All you need to know

Published: 10 September 2018

► AWD can be specced on most models
► 4wd system usually 40:60 rear-biased
► Can redistribute drive within 0.1sec 

Many premium manufacturers have their own version of four-wheel drive or all-wheel drive, and BMW’s is known as xDrive. Available on larger SUVs as well as smaller cars like the 1-series and 3-series, you can now get xDrive on most models from the German manufacturer.

It's a rival to Audi's Quattro system and the 4Matic set-up at Mercedes-Benz and is designed to provide extra traction on low-grip surfaces such as snowy roads or rain-dampened tarmac.

BMW claims that xDrive is lighter than rival systems, features a greater degree of traction splitting and can even respond to changes in grip faster than other all-wheel drive set-ups.

BMW xDrive: how it works

xDrive is a full-time all-wheel drive system, rather than a part-time drivetrain; systems like VW's Haldex differential only fires surplus torque to the opposite axle when the car’s on-board ECU senses wheelslip. So under normal conditions, BMW's xDrive is rear-biased, sending 40% of drive to the front wheels, and 60% rearwards.

However, this can be altered in one tenth of a second, with almost 100% of engine torque being applied to the front or rear axle, depending on grip available. This is allocated by an electronically controlled multi-plate clutch, rather than hydraulic fluid.

After normal driving conditions return, the system reverts back to its 40:60 split. More recent and high-end models combine this system with BMW’s Dynamic Stability Control to help rotate the car into the turn by braking individual wheels and cutting power across the axle.

By the CAR editorial team

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