I'll assume your talking about a class C since that's the only rig you mention by type.
And imo, there are plenty of variables to consider when deciding what is the right inflation amount for you, but here's my general take on what I do.
Trailer tires I almost always keep at max psi. Little 14-15" c and d load tires need all the help they can get with heat and tire scrub etc. plus I don't drive slow. If the truck will pull my boat or sled trailer at 80 mph, guess how fast I'm getting there?
Heavy trailer tires, my only experience is with tag trailers, equipment trailers etc and those go max psi cause never know what I or someone else might load it up with.
I also don't believe the over inflation tread wear issue is nearly as pronounced on narrow tires.
Vehicle tires are treated completely different for me. I run the pressure needed for the load, conditions, or season. I'll still err on the high side unless more traction is needed in the winter though.
Btw I've never even looked at an inflation table. After a while you get to know what pressures make you, the vehicle and the tires happy for what you're doing with it.
That said, I'm not changing pressures daily and don't freak out if I load the truck up at Homie Depot and drive 30 mi with only 40 psi in the back tires.
Jmo
