Just replaced rear tires (Michelin) after appx 20,000 miles inner edge down to cords, outer still with lots of use Discount Tire patiently explained this due to factory setting of negative camfer to offset normal (?) agressive driving of these Crossfires as well as Mercedes and BMW similiar cars while they could not correct suggusted others but in contactong them they could but did not have the necessary parts anyone tried this to extend the milage? successful ? where to get parts? any help will be appreciate