ST tires are required to be labeled for trailer use only as the renamed 16" Sailun S637 are.
I have 6 S637 on a triaxle GN stock trailer. These tires are over 6 years old and over 28k miles and were the LT designation before Sailun did the re ID for the 16" S637 for cheaper import tax reasons for P and LT tires.
If you want the tire to last 7-10 years and 60k-80 miles of trouble free service keep them pumped to max sidewall unless you pulled a newb and way over tired the trailer. A 3750-4400 lb rated tire isn't the best idea for a trailer with 2500-2800 lb per tire load.
Then pay attention to what tire experts tell us about ply shear regardless of the tires load range or psi in them.
If you use a commercial grade G load tire for 2-3 years and 20k-30k miles at 80-85 psi then it can take abuse like that unlike a lessor grade tire.
There is pages and pages for reading what tire experts tell us about best tire pressures for trailer use and the reasons why like our resident tire engineer Roger Marble in his rvtiresafety.net blog.
interply shearLots to read but will help anyone better understand interply shear in all tires especially a 110 psi tire with only 80-85 psi in them.