Thanks. And I've published this link before:
http://www.carlisletransportationpro..._Practices.pdf
Years back, I had also saved a link to a DOT study done that in one portion of a huge document specifically addressed the effects of age on ST tires. It was such a big document that I didn't save anything but the link, and now the link is no longer active. The bottom line though was that age has more of an impact on ST tires than passenger/truck tires. It also found, like the Carlisle link above, that more regular usage of the ST tire, when properly inflated and not allowed to be overloaded or overheated was actually better for the life of the tire than sporadic usage. Since my TM is most definitely in the "sporadic usage" category, I'm going to stay with 5 years from the date of manufacture as my "maximum."
Dave