2001 Ford Explorer tires problems

I am not the owner of this vehicle, nor the driver. My brother-in-law was a passenger in the ford explorer and was killed at the scene. There is a question of whether he was wearing a seat belt and if it failed during the rollover of the vehicle. There is also a question of firestone tire failure. Both of the rear tires were missing the valve stems. We do not know if this occurred during the accident or if they blew out previously and that is what contributed to the accident.

Tl* the contact owns a 2001 ford explorer with goodyear wrangler rt/s tires, size p255/70r16. The contact noticed the rear passengers tire was flat and the remaining three tires exhibited signs of dry rotting. The vehicle was towed to a local tire shop. The mechanic advised they would take partial liability for three of the four tires and the fourth would be replaced at the owners expense. The contact believed the tire manufacturer should take the liability for all four tires. The DOT number was unknown.