ON 10/1, UNIT WAS LOCATED AT MILE MARKER 153 ON I-40 NEAR ASH FORK AZ, WHEN THEIR FRONT PASSENGER STEER TIRE'S TREAD DETACHED (MICHELIN XZA 3+ 275/80/R22.5 DOT#M5EJ00EX3213). THE TREAD ACTED LIKE A FLAIL AND CAUSED APPROXIMATELY $12,000 IN DAMAGE TO THE VEHICLE. THE DRIVER WAS ABLE TO MAINTAIN CONTROL AND BRING THE TRUCK SAFELY TO THE ROAD SHOULDER. A STATE TROOPER WAS CALLED TO THE SITE. ONCE HE ARRIVED, THE TROOPER INSURED THAT THE TRUCK WAS SAFE FROM TRAFFIC AND INSPECTED FOR DEBRIS/CAUSATION. HE FOUND NO DEBRIS TO CAUSE INCIDENT. HIS OPINION, ALONG WITH THE DRIVERS, IS THAT THE TIRE FAILED. THE TROOPER WOULD NOT PROVIDE AN ACCIDENT REPORT AS NO OTHER VEHICLE WAS INVOLVED AND NO PROPERTY ADDITIONAL DAMAGED. THE TEAM PERFORMS REGULAR VISUAL AND PRESSURE INSPECTIONS. THE TRUCK WAS DISABLED FOR WEEKS FROM THE INCIDENT. ONCE REPAIRED, THE TEAM NOTICED WHAT APPEARED TO BE READ SEPARATION ON THE MATCHED FRONT DRIVER STEER TIRE (SAME DOT#) AND REPLACED TIRE FOR SAFETY REASONS. TIRES ARE BEING HELD FOR ANALYSIS. *TR