^ Agree, simple is good!
Normally, an OEM RV trailer tire has just enough capacity to cover the trailer weight when it is fully loaded. That capacity is usually at max sidewall psi.
When things change, is when the owner decides to go up in rating/capacity/higher psi max. One size, say D rated to E is a good thing if D is right at the edge. In this example, on an ST tire, you still can't go wrong with max pressure, or close to it. The problem comes, when the owner thinks he should change from Ds to Gs, and use only 2 thirds of max. A heavy tire, with low psi is going to have more rolling resistance, and run hotter.
Jerry
