Tire Tread/belt problems of the 2000 Chevrolet K3500

2000 chevy K3500,I have had 5 tires replaced under warranty tread seperation. None of them had the tread come completely off due to the fact that I am a shop foreman/technician with 25 years in the business and maintain my vehicle religiously. Pressure was adjusted to 65 front and rear when towing. 65 front and 50 rear when using as a daily driver. None of these tires had puncture repairs during thier use. They all seperated in the exact same place, the outside two rows of tread is were it would start. Front or back it didnt matter. The truck would develope a vibration and I would bring it in and have the tires checked. They were ameritrac 550 as 245/75r16. I have wittnessed many tires of this size and brand develope the exact same condition and many of them will blowout and damage the vehicles severly. I finally replaced all of them with a different brand because I didnt feel confident that they were safe to travel out of town on. I retained the tires that came off with the exception of the one that had seperated for the last time. I work for one of thousands of gm dealers acrossed the country and I am shocked at the number of tires that we see with defects. My current position is shopforeman and yes I am in charge of the tire department. The other brand that I see alot of with complete tread seperation and the tire is still holding air is the firestone steeltex 245/75r16. I am note sure how all the politics work between the tire man. And the auto man. But it sure seems that alot of this must be going unchecked by the agencies that are regulating defects. I write as a concerned citizen.

Vehicle started vibrating while driving on interstate 10 on may 3, 2001. At first we could not see any visible problem so we slowed our speed to well under 50 mph. We took vehicle to firestone store and the tread separation is now very obvious. The firestone store said they will replace tire with another firestone tire but they claim the steeltex tire is safe and does not have tread separation problems. This vehicle is a gm cutway, made into a class b motor home by roadtrek (home and park of canada). It is one year old and has original firestone tires. We have not driven it offroad, over medians, curbs or shoulders (this is what firestone has previously claimed was problem with emergency vehicles using steeltex tires). We did not have an accident but the tv in the motor home quit working as a result of the vibrating. (dot number: dn11bia299 tiresize: lt24575r16).