Here is the link to look up your tire plant codes to see exactly where your tires were manufactured.
Tire plant codesit is doubtful, but not completely unheard of, where a tire manufacturer in China left off some of the gum strips specified by the engineer. Basically this was a change that was made to the tire AFTER it got USA Federal approval. here is the article.
Chinese tire problemI am not saying this happened on the tires that you have but the fact that USUALLY new tires ride and handle much better than old hardened used tires that your experience is somewhat strange.
