Hi, I don't doubt that many of the Marathon failures, and other brands, could have been caused by bad valve stems, From China. So for some, Tires-China, Wheels-China, and now Valve Stems from China. And in most cases the vehicle owner is blamed for these failures. [and pays for it too] I read the link/story about the bad valve stems and the posted comments from tire shop owners stating the customers were too cheap to pay extra for new valve stems. Well it is my opinion that the tire dealers are the cheapos; At the Ford dealer we installed new valve stems for free on all tire changes. Bulk cost is about $00.08 each.[eight cents each] That's cheap insurance for you cheapo tire dealers out there. My opinion!