Are your rear tires wearing to fast? Do your rear wheels look slanted from behind? Did you go for an alignment and they couldn't get it straight?
Me too. I burned thru 3 pairs of rear tires, before I finally got it fixed.
This is
NOT normal. This is a problem, and if you don't fix it, it will only get worse to the point where it is unsafe to drive. Yes the X5 was designed with a little camber, yes it is a performance/handling feature. But it should not be visibly slanted and your tires should last what they were made to last.
Its the rear suspension. You need to part#11 upper control arms (aka wishbone), part#2 lower control arm bushings (aka ball joints), part#4 integral link, and maybe even part#6 guiding suspension link.
See the diagram below... and/or click here
RealOEM.com BMW E53 X5 3.0i REAR AXLE SUPPORT/WHEEL SUSPENSION
I had all the above replaced and now my ride is straight. My wheel alignment came out perfect, and I'm sure my tires will last what their supposed to. If you in the NY area and you want a referral let me know. My mechanic charged me $1000 including parts, labor, and a wheel alignment. And I got my car back the same day.