When it comes to tires there are several possible issues....
1: CHEAP.. (China Bombs) Some RV makers buy Michelin Some "Lowest Bidder" and some will get a grade light on the tire to save $$$ and increase profit I suspect (Can not prove)
2: Do you know the Cargo Carrying Capaity of your RV? (I do, and it's not much)
People blow the tires up to either A: A standard pressure (IE 27 psi) or ...
To the sticker pressure (Might be 28, Might be 35 might be XX)
or to the pressure molded in the sentence
Maximum load xxxxx at maximum pressure of yy
All 3 are usually WRONG so the tire ends up ... In many cases, UNDERinflated for the load applied..
And finally.. Not all states do a good job of road maintenance.. South Carolina cost me an engine believe it or not. (Thankfully Nationwide Insurance paid).