I noticed it at 9000 miles on my non-sport 4.4 on outside front tires. I think the alignment has been out since purchase. This should not happen. Get it fixed. You can get a 4 wheel alignment and balance. Take your banker. It wasn't cheap. More poor quality control by BMW. If mine continues to cup (I rotated the cupped tires to the rear, and put the uncupped rears on the front), I'll complain loudly. Cupping is abnormal. Sign of misalignment, bad steering or suspension components, and out-of-balance sometimes.