Tires replace all 4 or are just 2 OK?
 

Rear tires on my '05 X5 3.0 are worn. Can I just replace them or should I replace all 4? I have read that the ride will be adversely affected if all 4 are not replaced because it is all wheel drive? :dunno:

i was told that its okay as long as the the front tires are the same.(by my dealer)
if the front are off, the car could pull one way.

That sounds like the best solution

You may still need to replace the front tires, but before you do you could check all four tire pressures. If there is a significant difference front to rear, you could have the same symptoms.

I thought that running diffrent tires front to back could mess up the transfer case on an all wheel drive.

The only thing that matters for the transfer case is the rolling diameter. If it is too much of a difference, then yes it can affect the transfer case.

BMW recommends up to 7 psi different front to rear, depending on expected load, so they obviously expect some difference in rolling diameter.

I prefer replacing the 4 for an ideal balanced grip. I don't have the guts to have the rear and front axles of different grip... maybe i am just imagining stuff, but i have a feeling that if you enter a fast curve on a wet road for example, chances are much higher to go over/under steer in case you have different tires front/rear (old vs new)

Put new tires on the front and drive normal again - lesson: don't be so cheap. Thanks to all for the quick and insightful responses!

If you are only replacing a pair of tires, they should be placed on the rear axle. New tires go on back.