general problems of the 2004 BMW 530

I have a 2004 BMW 530i with "run flat" tires. The rear set of tires outside tread seemed to be in good condition and the front tires were also in good shape however, when I took the car in to rotate the tires the rear set of tires were completely worn on the inside and the tread was beginning to separate from the rest of the tire. This was the an observation made by the service manager, susan, at rouse tires in oakland, California. As of 5/1/2008, I have replaced all four tires.