After fueling up at Love’s, we weighed our coach and truck on a CAT scale there:

Here’s the report via their handy app:

These weights are within the acceptable ranges for this coach; the front axle rating is 16,000 lb, and the rear is 24,000 lb. This was weighing it fully loaded with our stuff, a full tank of diesel (150 gallons), 5% fresh water, and empty grey and black tanks.

I found this advice on the tire pressures:

Here’s the formulas:

Front axle weight/2 X 1.05 = Weight to look up in single wheel chart. Add 5 psi for your final inflation pressure.

Rear axle weight/2 x1.05 = Weight to look up in dual wheel chart. Add 5 psi for final pressure.

The 1.05 is used to estimate side to side weight differences that you will see when you do individual wheel weights.

And finally, do not inflate a tire less that 80% of the max side wall pressure.

So for us, our front axle weight (14,980 lb on 2021-10-29) / 2 (for each side) * 1.05 (to offset side-to-side differences) = 7,864.5 lb (for weight table).

Front tires are Michelin 315/80R22.5, rated max load 9,090 lb (for single) at max 130 psi cold, so table says 110 – 115 psi; should go with higher.

So front tires should be at least 115 psi for us. A bit higher (less than 130) is okay, but gives rougher ride.

Rear axle weight (23,220 lb on 2021-10-29) / 2 (for each side) * 1.05 (to offset side-to-side differences) = 12,190.5 lb (for weight table).

Rear tires are also Michelin 315/80R22.5, rated max load 8,270 lb (for dual) at max 130 psi cold, so table says 90 – 95 psi. But 80% of the max pressure of 130 psi is 104 psi, so that should be the minimum.

So rear tires should be at least 105 psi for us. Though when I posted about this in the iRV2 forums to check my math, there was some skepticism about the 80% rule. Still, 95 to 105 psi is within an acceptable range.

According to the tire pressure monitor, the coach tires are all currently around 115 psi, which is perfect for the front ones, and a little high for the rear, but still good: