We also have a 2007 Dodge Caliber with the Dunlop SP50 tires. I have always wondered if there was a problem with the front end because of the road noise. It is my wife's car and when she takes it to the dealer they say nothing is wrong with it. I noticed that the back tires are cupping / feathering quite significantly. I find it odd that the rear tires would do this with proper inflation and alignment. This seems to be a consistent problem with the Calibers and the Dunlop SP50 tires. One person even mentioned having to replace the front end bearings... sounds like a recall to me.