I haul horses for a living and I own horses as well. There are no 1700-1800# race horses ... ... ... ... trust me. A big fat retired race horse may go 1300# or so.
I haul as many as 6 belgians (as much as 1700lbs each) at a time on 7000# axles and LRG tires. I've posted this before, but I'm done with the LT tires ... ... ... . period!
I am currently running the Hankook 7. 5x16 LRG trailer tire and don't burn the sidewall out running as long as 18-20 hours a day without long breaks. I give the horses breaks every 3 hours or so, but the tires aren't gonna cool down much in 30-45 minutes. I've literally ran the sidewall out of LT tires, even the GoodYear Marathoner which is supposed to be a trailer tire. When the tread part of the tire comes off like a doughnut, and you have nothing left on the wheel but beads and part of a sidewall, the sidewall is over heated.
Tires are rated at 105PSI and I run them at 90PSI, I run 10,000 to 15,000 miles a month and I'm convinced.