I purchased my used Class C form a dealer and it had new tires on the front and not so new on the back. This information was offered by the dealer and they showed me the invoice. They were american made tires. What they did not say was the tires had been warehoused for several years. I was lucky to have my left front tire go bad within 3 months of the purchase of the RV. I lost a lot of paint from the wheel well as the tire turned into a wire brush while I was at a cruising speed of 70 for many hours. Had it not been for the change in steering control I would not have pulled over, which may have saved the lives of my passengers.
Tire manufactures constantly over produce tires so they do not have to lay off people, then store them for sometimes up to 9 years according to a news report aired sometime near 2000. These tires actually become defective while they are in storage. The industry is aware of this practice and tend to self control itself, but not all persons are willing to destroy stock they paid good money for, and the tires continue to degrade while they wait for an unsuspecting customer.
I learned the hard way to look at the tires and their manufacture date. New is pretty, but it can also be deadly.