BMW vs Winter: all you need to know about BMW xDrive

By the CAR editorial team

21 January 2014 15:00

According to BMW, its ‘xDrive’ all-wheel drive system is more popular than any other premium brand’s four-wheel drive drivetrain. That’s right: in the UK, xDrive outsells Audi’s famous quattro system, not to mention Mercedes ever-expanding 4Matic range, and all-wheel drive version of Jaguar’s XF and XJ.

If you had to name an all-wheel drive BMW off the top of your head, you’d probably plump for the X5, but the truth is that xDrive has infiltrated the majority of BMW models. In the UK, you can spec xDrive on the 1-series, 3-series (saloon and estate), plus the X1, X3, X5 and X6.

The upcoming X4 is expected to offer xDrive too, and a 4-series xDrive model will come on stream later in 2014. In left-hand drive markets, you can also spec xDrive 6-series and 7-series models.
BMW also boasts that xDrive is lighter than its rivals' all-wheel drive systems, offers a greater variability of traction splitting, and responds to a loss of grip faster than quattro or 4Matic. Big claims, but how does xDrive do it?

xDrive is a full-time all-wheel drive system, rather than a part-time drivetrain which only fires surplus torque to the opposite axle when the car’s on-board ECU senses wheelslip. Under normal conditions, it conforms to BMW’s rear-biased trademark, sending 40% of drive to the fronts, 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.

This is allocated by an electronically controlled multi-plate clutch, rather than slower-to-react hydraulic fluid. After normal driving conditions have been established, the system reverts back to its 40:60 split. Higher-specification models, such as the X6 SUV, combine this with BMW’s Dynamic Stability Control to help rotate the car into the turn by braking individual wheels and cutting power across the axle.

CAR has put xDrive to the ultimate test in our BMW vs Winter supplement, available as a free-to-download app and a print magazine with the February 2014 issue of CAR magazine.Find out more by clicking here.

By the CAR editorial team