Tire Tread/belt problems of the 1999 Oldsmobile Intrigue

Consumer has goodyear, eagle, p225/60r/16, replacement tires, 31000 miles. There was tread separation on front two tires.

3 of the four tires, both front and one rear, have bubbling on inside edge with tread seperation. It sounds simular to the firestone problems. I find it perplexing that these tires lasted less then 37000 miles before they had tread seperation. As soon as I noticed, I replaced all the tires with another brand because I did not want to risk a blowout. It is difficult to notice this particular seperation because it occured on the inside edge of the rear tires. I noticed it only because something did not sound right and I located the faulty areas by feel. I am concerned that if this is a wide spread problem, some might not notice before the seperation becomes worse and/or a blow out occurs. ( dot number: m6xobmwr24 tire size: p22560r16 ).