Hello Mike, I am David Sneed, 166 Wesley Rd. Green Cove Springs, FL 32043, my ride is a 2006 BMW 650i @ 38K. My question concerns alignment targets and rear tire ware. I purchased this car 15 months ago with 24K miles and am now on my third set of rear tires, same front tires. Each time I replaced the rear tires, the outside of the tire looked new but the inside was down to the cord. The car has been aligned twice last year (Jan 08) at BMW before the first new set and then in December 09 by an outside alignment shop as I wanted another opinion. The target camber on this car calls for -2 on the rear axle which I thought may add to the way the rear tires ware so bad. I started to set @ 0 to see if I could get more that 6,000 miles out of a set of rear tires but decided to go back to factory specifications and send you a note for advise. Note, the second set of tires were not run flat as I was in rebellion against this concept but on the last set went back to run flats as the service manager @ Tom Bush BMW said that with active suspension, run-flats would improve the mileage I could expect form a set of rear tires (they offered no suggestion for what I consider to be extreem tire ware). Most miles driven have been interstate @ between 70-80 mph. Any suggestions? Thanks, David
Your service manager is full of crap. There is absolutely no tread compound difference between a run-flat and a non-run-flat version of the same tire (their sidewalls are constructed differently, but that is not the point of your question RE: tire ware). You are correct, however, that backing down on the aggressive negative camber will improve the inside ware on your rears. My 545i, and most BMW's from my understanding, suffers from the same inside ware issue. It's a performance vs. long life trade-off that BMW is willing to make, simply because they sell performance cars (don't have to pay for replacement tires). CLG
