You gotta pick your Rim Size at the top of the Load/Pressure Chart. I selected 19.5" thinking that's what you have. I don't know if the chart will show that page in the link I'm sending or not.
If you get stuck, go to a Truck Scale (like CAT, costs $10) and get Front and Rear Axle Weights. They'll be called Steer and Drive. If you have a Toad or Utility Trailer tow it onto the Scale and it'll show as Trailer.
Post what you get, and if you can't get the chart to work, I'll look it up on my real computer and give you the pressures.
1. "sidewalling" the pressure is rarely right.
2. handling depends on proper front pressure
3. you can use one manufacturer's chart for another's tires so long as all the specs match
4. single and dual have different capacities so use the chart carefully
5. some Michelin charts are for Corner Weights (which CAT won't give you) so you may have to double the chart values to compare with CAT weights.
Willing to help. I'd need the exact nomenclature of the tires as well as the axle or corner weights. Let us know!