For motorcoach tires, we calculate the weight on each corner and use the manufacturer's tables to set the PSI. Basically weigh each corner with the coach loaded for travel. Use the highest weight found on an axel and set both ends of the axel the same based on the table.
Wife's '20 Fusion is a Titanium so the stock tires are wide and low profile 235/40R19 and there's not much air volume therefore every dip near 20°F causes the TPM to alarm on at least 1 tire. Normal suggested is 37 PSI, I go for 40 at start of winter.
