I don't know what your trailer is in terms of weight, but many of us that have pretty good size RV's have gone to the LT (light truck) tires rather then the trailer specific. The Goodyear Marathons have of late become garbage as many sizes are being made in China. These have had many problems with tread separation, sidewall bubbles or just plain unexplained failures. Then there are those that are many years old even before they are sold and mounted. Carlisle's have been reported as having significant problems as well, The Maxxis, so far have reportedly been pretty good. Pretty much the folks that have my size and weight trailer (35' and up 5th wheel) have gone to Michelin LTS, Goodrich T/A or in my case, General Grabber and in 10 ply 'E' rated LT's.
Take a look at this site
and just do a search on 'tires'. There is one guy who swears up and down that TT's need ST tires, and he is getting boring as he is dead wrong.