If you feel up inside the rear fenders/body panels you can feel a metal lip that sticks out. It's possible that lip is making contact with the wheels when the suspension compresses. You can roll the lip up so that it gives you more clearance. I've read about using a baseball bat on the tire to do it but I couldn't figure it out. I ended up using some vice grips to just grab the lip and bent it back. It turns out that wasn't what was rubbing on my car though, but rather the inside of the wheel was making contact with the top of the rear suspension (it's hard to diagnose by yourself). I took the upper dog bones off (goes between the top of the trailing arm and the body, I call them dog bones because of the shape, I guess their upper control arms) and ground the outer edges off and I haven't had any problems. I still rub the front sometimes when I hit a good bump or put the car on an odd angle but the rear's been okay. I also have a camber problem in the rear that needs corrected and might cause problems once the wheel is pushed back out though. I just basically count a set of tires to only last 1 summer though.