Local tire shop had PowerKing Trailer King RST available in a E load rating. Got 3 - 2 main and 1 spare. Had em for the season and so far no issues. I replace the tires every 3-5 years, even if they don't look like they need it.
At 12 years it was well beyond its life expectancy!!! Just had a flat repaired last week....the tire shops will not touch any tire over 7 years old, other than to replace it!! Supposed to be a new regulation...some shops now consider 1/8" tread as worn out, so no repair on those either.
Yep, the tire mfgrs get together and decide what is best for them, then get it apporoved by the transportation safety board. I can remember when new tires had 3/8" of tread depth or more in some cases, byt not anymore if your lucky you might find 11/32, but many are only 5/16".... subtract the new 1/8" safety standard and your new tires wont last long anymore !!!