I purchased my 2011 BMW 335I X Drive mainly becausse it was a std. trns. (Six Speed); it also came with the M package which meant Run Flat Tire w. 225/40R18 in front and 255/35R18 rear. The Run Flats were Summer Only and in Rochester, NY we have Winter Only so I replaced the Fun Flats with the same size Non Run Flat Michelin Pilot Sport and the dealer gave me credit for the exchange. The front tires show hardly any wer after 30 k miles and the rear were replaced and after 12 k miles and they again need replacing. I’m over 70 so I don’t burn rubber and would appreciate your analysis about the difference in front-to-rear wear.
These cars have quite a bit of negative camber in the rear for handling. Camber is the angle from vertical that is set by the alignment. Negative camber means the tire leans into the center of the car from vertical. This car has almost 2 degrees of negative camber at the rear.
Now this is great for sporty handling but for more genteel drivers, this means the tire wears out on the inner shoulder at the rear. Ask your BMW service person if they can reduce the negative camber at the rear for better tire wear as well as the front so you maintain the safe handling of the car.
First, the front and rear tires are being asked to do different things, so you would expect them to wear differently.
As Mustangman said above, these vehicles have quite a bit of camber, so you may want to get an alignment where they dial out as much as they can. Oh, and the toe has got to be spot on - otherwise, the wear gets exaggerated.
I don’t know much about how the torque is split on these vehicles, but it wouldn’t be unusual if they act more like a RWD - and therefore the rear tires are doing all the grunt work, and might wear faster.
It seems from your post that you don’t rotate your tires. AWD vehicles should have the tires rotated about every 5000 miles or so. This will even the wear, but you will have to replace all four tires earlier. What does it say in your owner’s manual about tire rotation with X-drive?
Thank you, JTSanders for posting the same questions that were in my mind!
If the OP did actually rotate his/her tires, I apologize for the assumption, but–in view of the fact that there was no mention of tire rotation–I have to assume that the tires were never rotated, and that was a major mistake.
You’re correct!
I missed that detail earlier.
Perhaps that is just one more reason to not buy a car with different tire sizes on the front and the rear.
If the tires are wearing on the inside edges (usually the norm) then there’s an excessive negative camber issue.
You may need to correct it with a kit like this. The problem is not that rare. I have no connection with the seller. Just linking it to provlde an example.
