Poke around this RMA = Rubber Manufacturers Association site for all kinds of tire info.
https://rma.org/

Also, ever wonder who made your tires? Don't laugh, the sidewall name may not tell the whole story, as for instance some recalled Good Year tires were made by Michelin North America!!!
Anyway locate the DOT plant code on your sidewall, it may be on the back side of the tire as mine were, then look up who made them here http://www.harriger.com/tires.htm

Enjoy the info, I sure have over the years.