AFTER DRIVING APPROXIMATELY 20 MINUTES AT A SPEED OF APPROX. 30 MPH ON A GRAVEL ROAD FIRESTONE WILDERNESS P265/70R16 REAR TIRE BLEW OUT ON MY '01 GMC YUKON WITH COMPLETE TREAD SEPARATION, AND THE RADIALS BREAKING. MY HUSBAND CHANGED THE TIRE WITH OUR SPARE THAT IS THE SAME MAKE/MODEL. APPROX. 10 MINUTES LATER ON A PAVED ROAD AT A SPEED OF 45 MPH, THE SPARE BLEW OUT WITH COMPLETE TREAD SEPARATION. OUR VEHICLE WAS TOWED TO THE DEALERSHIP, AND THERE WAS NO PROBLEM FOUND WITH THE VEHICLE. THEY BELIEVE THE TIRES ARE DEFECTIVE. WE HAVE REPLACED ALL FOUR TIRES ON OUR VEHICLE AND KEPT THE FIRESTONE FOR EVALUTION AND ANALYSIS PURPOSES.*AK