Tire Blowout problems of the 2006 Nissan Xterra

I had all four hankook dynapro atm tires from this batch replaced for tread separation. I originally purchased these tires in March of 2010. I had two of them replaced in April of 2013 (the separation on the two tires were so bad that they would not let me leave the shop with them. ), then the blowout in September of 2014 then the final replacement in February of this year. All of these tires were replaced due to these defective tires. I replaced these tires with the same product thinking I just got a bad batch of tires. But when showing the guys at the discount tire what happened to the tire and car when the tread blew off the tire and the 2500 damage that was caused to the SUV, they felt that that was a defective product and that I needed to file a claim with hankook. They helped me get the claim started. I was contacted by juan britos who asked me to send in an estimate from a repair company which I did. A few days later I received a letter stating that the claim was denied due to “prolonged operation of the tire in an under-inflated state” this claim is simply untrue. I commute quite a few miles a week. I am very conscious of the pressure of my tires. I do this for economic reasons I know keeping properly inflated tires improves mpg. This is why I keep a tire pressure gage in the door of my car and check it regularly. I also keep an air compressor in my car to inflate any under inflated tires, this is also an automatic shut off compressor that shuts off at the set psi. I keep my tires at a range of 35-40 psi. I also have a tpms system in my vehicle that would warn me of any low pressure issues.