Some of the tires from Interco are made in China. Those 42" SX2's used to be one of them, also the 40" & 47" LTB's, Irok ND's and a few others. They may have moved the molds over to the US now though, not sure but I do know a lot got moved back over here. Sounds like this may be the issue with the ones saying the compound is different than a lot of their other tires. I had a set of the 40" LTB's several years ago and they were a China tire. Didn't keep them long but I did notice the compound was different. Hope this helps