Proper Tire Presure

ST tires are best run close to or at max psi as stated on sidewall. There should also be a white label, most often placed at the front corner of the trailer by the TT manufacturer that will indicate proper inflation psi. Every label I've ever seen at the dealers lot or RV shows always uses max psi of the ST tire installed on the trailer. Filling an ST tire to far below max psi will cause it to overheat, issues including tread separation and catastrophic failure are often times the end result.

If your RV came with that size then the answer is use the MAX pressure marked on the tire.

There are at least 100 topics on this. It has to do with the weight on each axle and tire . . . Do a search