We had 2 TTs before getting our MH. Whenever I replaced tires, I always went with LTs (Light Truck) and 1 size bigger and the highest load range I could get. We never had any tire problems on either trailer (knock on wood) because as soon as I saw the slightest cracking taking place I swapped tires. We ran both trailer thousands of miles over the course of 30 years.
Here is a link to a WalMart listing for an example of the tires I would purchase
http://www.walmart.com/ip/Michelin-LTX-M-S2-Tire/15103306
Best of luck in your hunt for new tires.
