Thoughts ??
Your HH Discover America has 7k axles and has a 16200 GVWR. Now subtract 3k pin and your looking at approx 13k-14k on the axles or 3250 lbs to 3500 lbs per tire.
looking at a 17.5 Goodyear G114 H tire says they have a 4800 lb rating at 125 psi. Now you have a H tire with lets say a 3500 lb load. That means your going to have to derate the tires pressure significantly. I don't have a chart but lets just say down to 100 psi. Now the H tire is a big heavy tire and big heavy tires heat fast and can quite high temps especially carrying a 3500 lb load with those lower pressures. The tire is hot and pressure builds.
Now on the flip side if the H tires were carrying a 4200-4400 lb load and the pressure was cold set at 125 those tires will operate cooler. There is a trade off when we over tire a trailer.
As others have said tire makers know a tire heats with speed and ambient temps. I have no idea how much pressure would be the best for your tire situation other than weigh your trailer axles and divide by four = load per tire and consult your tire makers pressure charts.
Its been my experience with several equipment trailers on the road in the high passes in northern NM/CO tire pressure wasn't affected by altitude.
I like this suggestion for a over tired trailer;
rvsafety.com
Tire Load and Inflation Ratings
Note: Towable – Travel Trailer/ 5th Wheel owners Due to the severe use conditions experienced by tires when axles are very close together – tire industry experts recommend maximum (sidewall) inflation pressure for towable tires unless this causes a sever over-inflation situation (20psi+), often referred to as the ‘basketball effect’. If this is your situation allow a 10 – 15psi safety margin above the minimum required inflation pressure.
