I have a 2007 X5 with the sport package. This includes the 21" staggered wheels. I bought new replacement tires 8,000 miles ago in September 2011, 4 tires mounted, balanced and a 4 wheel alignment. Got 45,000 miles from the last set. Now I notice extreme wear (bald) on the left front tire outer edge. Looks like a tire out of alignment kind of problem. Dealer checked out the suspension and said tie rods and bearings are good. He said the tires were cupping and just wore out. He also said BMW has had a hard time keeping tires on X5's, "they eat tires", and their fix is to sell you new tires and alignment. If the steering wheel position does not indicate an out of alignment condition and it doesn't 'pull' to a side, what other indicator will advise you of an alignment problem before you see the tire wear? Now I must consider changing wheels and tires to a common set due to this problem which requires new tires every 9 months. Is it just my vehicle or has anyone else experienced a problem like this? Has anyone else heard that X5's eat tires?