NHTSA Complaint #11585713 — 2006 CHEVROLET SILVERADO 2500

265/75R16 9100 miles driven mostly on pavement with loads well within the vehicle capacity and never off road. Tires were rotated several months prior, about 100 miles ago and damage was not noted. Bubble appeared on sidewall which was noticed while parked; Tire shop dismounted the tire to inspect for possible causes and found nothing to explain damage (run flat, left deflated, road hazard damage). Secondary bubble slightly smaller on inside at same location. Smaller bubbles were felt inside tire and a longer, slight bubble follows the bead 1/3-1/2 of the diameter of the tire. Shop manager refused to remount tire due to risk to employees of catastrophic failure, indicating the tire poses significant safety risk if vehicle had been at highway speed and completed its deterioration. Mate to this tire on right rear shows same smaller bubble above the bead about 1/3 of tire diameter.