Trailer wheels - 65psi?

I ran E rated tires at 80psi for 5 years on 1875 lb rims. No problems.

Your wheels can handle 65 psi .
This has been discussed frequently .
The wheel weight loading is a such higher demand that 65 psi is not even a consideration .
CapriRacer floated the idea recently that even if a wheel was stamped 65 psi that he would consider using a load range E tire at 80 psi because the tire is by far the weakest link .
It is a common misconception that RV wheels have some psi limit .
Only a few aluminum wheels are stamped with a psi limit .
The tire is always the weakest link in the tire / wheel combination .

Ok, that's what I was afraid of - needing 4 new wheels.

So since I may be buying new wheels, is there a better size that I should move to? I am currently running 205/75-15. I've heard that moving to LT tires is the best idea, so maybe this is a good opportunity to do that?

Max for that rim if stamped with 1870 lbs is 50psi. Good idea to upgrade to bigger, higher capacity ST tire, will improve durability and overall longevity while reducing occurrence of castrophic failure. Best to upgrade rim than to run ST tires at lower than max psi as stated on the sidewall. We've experienced reliable service from our Maxxis tires over the last 4 years.