Tire Sidewall problems of the 2003 Ford E-550

Firestone steeltex lt265/75/r16 r4s tires - sidewalls are separated at the raised letters. This issue was identicle on all 4 tires. Tires were original equipment on a Ford excursion - 2003 2wd diesel. Tires currently have 48000 miles with good tread remaining. I can lift up the lettering and see the sidewall fibers on the sidewalls. This vehicle is never used off road and specifically used for long distance travel. I am going to replace these tires tomorrow, 3/21/2007. I have not at this time had a blowout or flat tire but these tires are extremely unsafe.

Tire defect: goodyear wrangler rt/s p255 70r16 - side wall cracks on 3 of 4 tires. Vehicle: 2003 Ford truck f-150 4x4 mileage: 53000.

While driving to work on the freeway I noticed my 03 f250 crew cab 4x4 started to pull to the left. I realized I was getting a flat. I noticed my rim was damaged(cracked) allowing air to escape from the bead area. The tire was not deflated when I pulled over but in a short time it went completely flat. I was told the wheel was defective. It was replaced and the original tire that was on the damaged wheel was mounted on the new rim. They put the wheel/tire in the bed of the truck . The next morning at apprx 10:00 am(apprx 68 degrees out) the tire exploded. Was blown out toward the middle of the sidewall and ripped back toward the tread. The cords and rubber where pushed from the inside out. The tire was thoroughly inspected by more that one professional prior to it being installed on the new rim and they all agreed there was no damage. I did not strike anything and the air pressure was apprx 45 psi. The max air pressure on the tire is 65psi. I took it back to the shop. They dismounted the tire from the new rim and had it inspected by parnelli jones reps. The reps claim I struck something even though there was no evidence to show that(scratches,cuts,bruising etc ). I also know that they are being less than truthful do to the fact I know I didn't hit anything! these tires are 38x15. 50-17 are 10 ply and e rated. I asked for an explanation as to how it could blowup while sitting in the back of my truck not under a load. They had no explanation for me other than u must have hit something at one time or another. Ivy never hit anything and ive never off roaded the truck. The inside of that damaged tire also showed signs of the inside rubber splitting from the seems. One of the other tires that is mounted on the truck is cracking on the outside sidewall apprx one half inch above the bead. It runs all the way around the tire and is apprx an 1/8" deep. All my other ties appear to be fine. The tires have been on the truck for 6 months. They have 10k miles on them.