Problems with 2001 Nissan Xterra TIRES

I purchased 4 firestone destination le tires in 2004 for my 2001 nissan xterra. after 24000 miles i noted that there were small pieces of the sidewall missing on all four tires - evenly spaced around the sidewall of the tire. on the rear passenger tire, the largest missing piece was approximately .75" on each side. i did not take pictures and i experienced no driving problems with the tires. i took the car back to the firestone store and they replaced all four tires at no cost. i am sending this because this clearly looks like some type of defect since i was seeing the same pattern on all four tires (and have never seen anything like that before). if other people are seeing something similar, i wanted to have it noted that i also had this issues. *nm

Dt*: the contact stated during an oil change the mechanic noticed the driver side rear wheel was fractured. the vehicle was operating normal prior to the failure. the vehicle was taken to the dealership where a spare tire was put onto the vehicle. *ak updated 05/16/06. *jb

Driver noticed that all four wheels had cracks inside and outside. this caused leaks from the tires and unbalance of the vehicle while driving. driver took vehicle to the dealer, and mechanic determined that the wheels and tires were operating as designed, but a flaw was noticed while inspecting. *ak

While traveling on interstate 75 in florida, the passenger side rear tire blew out. the car veered to the left and the front passenger bumper slammed into the guard rail in the median. the car spun around several times until the rear passenger section slammed into the guard rail. the car then stopped. the passenger rear tire was completely demolished and only a shell was left.the car had been into the dealer for its 15,000 mile check in july and the tires were rotated. the car was at the dealer for an oil change about one week before the indicent. the car had been maintained to the manufacturer's specifications and only has approximately 20,000 miles on it. mr