WE WERE DRIVING WITH CONTINENTAL TIRES (P265/70R17113S) ON AN ARIZONA HIGHWAY WHEN OUR REAR RIGHT TIRE SEPARATED. OUR VEHICLE IMMEDIATELY VEERED TO THE LEFT AND WENT UP A GUARDRAIL WITH A 30' DROP BELOW. OUR VEHICLE (FORD EXPEDITION) FLIPPED 360 DEGREES, LANDING ON ITS PASSENGER SIDE. THE VEHICLE WAS WELL MAINTAINED. THE TIRES HAD SUFFICIENT TREAD. THE AUTHORITIES ON SITE TOOK PICTURES OF THE TREAD SEPARATION AND RECOMMENDED REPORTING THIS AS THE TIRE APPEARED TO BE DEFECTIVE. *TR