Running the OEM tire inflation chart or perhaps a few pounds over gives the best compromise between smooth ride and tire life. On RV's the odds are the tire will age out before it wears out (unless you run heavy).
Second and far more importantly is the control
Inflation low: Excess flex in the sidewalls, plus the tendency of the tire to not make solid full width contact with the road REDUCES control
Over inflation: Only the center makes solid contact and again CONTROL is lost, plsu the ride is "Stiff".
Proper inflation gives full contact and maximum control.. This can be a lifesaver.
