One morning, I had a flat tire, the tire was taken off the vehicle, and taken to sears auto center. Visual inspection revealed no punctures or reason for the flat. Further inspection showed the valve stem had a large crack close to the tire itself. Needed to replace the valve stem. Brought vehicle home, and left in garage for the weekend, when taking the vehicle out of the garage on Monday morning, thought the steering was not as usual. Stopped the vehicle, and saw another tire was going flat. Then checked the other three tires, and saw all three valve stems had cracks in them. Vehicle taken to Firestone auto care for replacement of the valve stems. The tires had been replaced on the vehicle in November, 2007. Although the repair shops did not say why valve stems would have failed in such a short time of each other, I wonder if this may be part of the safety recall done for defective parts from dill air controls. Although the tires were purchased after the date indicated could there still be defective valve stems which were still being used on tires? sears only said the valve stem was not covered by warranty.

- Montville, NJ, USA

My 2004 Envoy after driving it for a year with no long road trips the tires had worn unevenly and two were almost bald. This is a short time for tires and they were rotated when need. The warranty covered replacing the tires and now it has been another year or so and they have do the same thing. GMC does not want to replace them again, they say it is normal wear. So my question is how many people replace their tires every year?

- Urbana, IL, USA