what's the main difference between BMW's AWD and X Drive?

the title says it all

any insights?

XDrive is a more advanced system of BMWs AWD from what I have read. For instance, instead of locking power 70/30 between axles, XDrive can put any amount of power from 0-100% to the front or rear depending on the conditions it detects.

That's how it was explained to me.

It would be interesting to hear an opinion from someone who owned an older X5 and a newer X5 with X-Drive to see how they compare in day to day driving in the winter. My guess is there would not be significant difference, despite the fact that the two systems are completely different.

Originally Posted by FireFly

It would be interesting to hear an opinion from someone who owned an older X5 and a newer X5 with X-Drive to see how they compare in day to day driving in the winter. My guess is there would not be significant difference, despite the fact that the two systems are completely different.

In this article the testers noticed that the new XDrive system causes understeer as it actively manages driving and tries to keep the vehicle under control.
http://motortrend.com/roadtests/suv/...rm/index2.html
We found the X5 produced terminal understeer even under full throttle in a high-speed sweeping turn, where two of the others' AWD systems seemed to overcome this tendency.

BMW's new xDrive AWD system is a departure from last year's, which used a planetary center differential to permanently apportion front/rear torque at 38/62 percent.


Same thing noted by one of the X3 drivers in the 2004 AlCan 5000 Rally.
http://www.europeancarweb.com/news/0408ec_aican/
Unfortunately, despite this victory, rallying is not xDrive's forte. The electronics that make the truck a dream drive for suburban moms with no winter driving skills worked us in competition. Pressing the DSC switch on the console can roll DSC parameters back, but the electronic nanny cannot be completely turned off--and it can roll those parameters forward again if it thinks you're going to crash. It did exactly that throughout the ice races.

ABS brakes are integral to the xDrive function, so they cannot be turned off. ABS maintains steering capability under maximum braking on snow and ice, but a trained winter driver can stop faster on these surfaces without ABS.


I if these gripes are because XDrive truly hinders performance under certain conditions, or if it is more a case of the drivers not being used to what they can do with the new system. I would suspect it is the latter (after all if XDrive really were not up to par the X3 probably couldn't have placed 1st in a 5000km ice rally), but that's something it will take time to figure out.