At the time of my third tire rotation, my dealer informed me that my tires were worn down to the wear bars and needed replacement. mileage at the time was only 19,474. gm would not take responsibility for replacement or partial re-imbursement of the general p225/75/r15 tires, even though they were factory-installed on the truck as purchased in 2008. the tires either were defective, or gm chose to put very poor tires on their new colorado trucks as a way of cutting costs. *tr