RE: Truck vs. trailer tires.  As was stated before, trailer tires are compounded differently because they sit a lot and stay on trailers for quite a few years.  Truck tires have a much shorter aging life than do trailer tires which also have stiffer side walls. Might void a warranty and/or insurance claim if it was discovered that somebody was running on truck tires.  It's cheap  insurance to find and buy a high quality trailer tire IMHO.
The question remains though, who makes high quality trailer tires?