Originally Posted by raroberts
My question is, when should I worry, how much over air temp is bad? how much over cold PSI is bad?
Ignore any increase in PSI over the cold inflation pressure. It's going to increase, and how much it increases doesn't matter.
Worry about decrease
in PSI that causes the tire temp to soar. Under-inflation - such as caused by a slow leak - is what kills tires.
If your TPMS systems allows you to see the PSI and temp in all the tires, then check it out when the tires are cold to be sure they are still properly inflated. Then don't worry about the PSI unless it goes down to less than the cold inflation pressure.
BTW I have very good tires on the trailer and the truck. GY G614s on the trailer...
Tires with not enough weight capacity for the load is the primary cause of trailer tire failure. However, your G-614 trailer tires have max weight capacity of 3,750 per tire when inflated to 110 PSI, or up to 22,500 combined GAWR if the weight is distributed evenly in the trailer. That's a 25% excess weight capacity, which in my experience should be plenty to prevent trailer tire failure. So I'd probably watch the PSI in the trailer tires and be sure it never goes below 110 PSI in any of the 6 trailer tires.
And it goes without saying that speeds over 65 MPH should be avoided. Yeah, I know, the big boys go the speed limit of 80 MPH in far west Texas, but the highway is full of "alligators" from those trucks, too.