This problem affects wheel style "296" a 19" optional alloy wheel package for e89 bmw z4. Bmw part number 36116785257(rear wheel 19x9) and 36116785256(front wheel 19x8. Under normal driving conditions, multiple cracks developed on inner edge of rim lip leading to large drop in tire pressure and potentially unsafe driving condition. This happened to (1) of my rear wheels. After doing research, I strongly believe this is a manufacturers defect as many owners of the same particular wheel model "296" are experiencing the same problems. It is noted in the following link: http://e89.zpost.com/forums/showthread.php?t=485935 contacted bmwna customer relations and they declined to provide assistance.
2009 BMW Z4 wheels complaints
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