Depends on what your trailers OEM axle ratings are.
For 5.2k-6k axle I use a good all season tread 16" LT235/85-16 E at 3042 lbs per tire. Michelin XPS Ribs and Bridgestone R238 are a commercial grade all steel ply carcass tire and are tops for those size axles
For My triaxle GN stock trailer with 7k axles I use Sailun S637 ST235/80-16 load G tire at max sidewall. In a heavy tire like a load G I personally wouldn't use any pressure less than 90 psi. Those are a very heavy stiff commercial grade tire and like all commercial grade tires they can run hot with lower pressures.
What ever tire that lasted 39 years I would stick with that brand...:B
"good judgment comes from experience, and a lot of that comes from bad judgment" ............ Will Rogers
'03 2500 QC Dodge/Cummins HO 3.73 6 speed manual Jacobs Westach
'97 Park Avanue 28' 5er 11200 two slides