Tires: shifted belts, goodyear wrangler tires, target value

Question
Hi, I was told that all my goodyear wrangler tires have shifted belts. They only have 20k on them and I always keep them inflated properly and the alignment good. The alignment shop is a tire store and I don't trust them. If its true, is it dangerous. The car is an explorer.
Thanks very much. Al

Answer
Al,

There is no such thing as a shifted belt.  People use this phrase in order to explain an irrgeular wear pattern that commonly appears on tires.  The real cause is misalignment and aggravated by insufficient inflation practices and insufficient rotation.

My experience says that the published alignment tolerances are too wide.  Not the target value, but the allowable deviation from that value.  I think it ought to be half of what is published.

Put another way, the alignment should be within the inner half of the spec.