So I was on Tire Rack this evening looking for options for a new ST tire for the HTT. Not many options for 13 tires.
I found interesting, while comparing the only two 13 tires. Both the Goodyear Maarathon and the PowerKing Towmax, tires are very similar. Under the speed rating of the tires both have an NR code, with a speed rating of 87 mph. That is clearly not the speed rating I have always heard for trailer tires. I think more research will be required.
By the way, I hate Tire Racks new website, it is nearly impossible to find trailer tires. But I did locate a good article about tire care.
website on tire care is very interesting.