Bud
It is what it is.
Carlisle tires were mentioned earlier. They are the most common sold already mounted tires from many a big box and sporting goods outfitters.They are "cost effective" .
After losing a few on several of the trailers in our control, and thru the years on family and friend owned, I avoid them.
The failures have been on loaded, unloaded, three year old and two less than a year old. In heat and in cold. No extremes I would consider above average.
I am a trailer nut about wheel bearings and tire pressures, and these were checked on the day they failed.
We replaced the Carlisles that came on our toyhauler two seasons ago after they all wore like front tires on an RT . I stressed all the way home after seeing the tread wear.
Went to the local tire guy who shook his head at my C's and talked me into a higher end tire...MasterTracks on the sidewalls.They are 8ply class e and have taken a few long trips without any wear stresses or worries on my part.
Have other friends with same experience with C's, so I don't think I am a tire snob.
+1
In my former life I managed a Goodyear Tire Center.
Good trailer tires are worth every penny if only for peace of mind.