Dually tire pressure?

Running empty or near empty, there’s absolutely no issue with dropping them to 25-30psi.
Think about the weight they’re seeing. 25-30 is the equivalent of 50-60 if you were running single.
Look at a load inflation chart and see what pressure it takes for 1000lbs (x4 = 4000lbs= empty dually). Bet it’s alot lower than that.

Yeah with the 5th or the Bigfoot I air them up.
At 65psi it beats me up. Bad streets and 3 back surgeries.
I might dip down into the high 30psi and see how it feels and what kind of pressure they build on the road.
Tow pro....y'all been getting rain? I'd like to get back to Spruce Creek. Was there last fall and it was up and muddy.

I have the same truck.

I run 40 psi empty in the rear. 400 lbs still means empty in my truck :)
in fact running PA to FL towing a 7x14 V nose with stuff in bed and trailer (moving) I was running around 50 psi in rear. Not a lot of weight, just a lot of junk moving.

with my 990 fully loaded installed on the truck I run 70psi because it felt better.

But mine is 2wd wich takes off about 400 lbs mid ship.

When towing I always use the recommended pressure shown on the sidewall of the tire, manufacturer website or door sticker. Low pressure causes heat and heat kills tires.