265/75/R16 tire pressure ? with empty bed

Changed my wheels & tires from LT 31/10.5/15 -> to 265/75/R16 .
My truck is a daily driver, but I load it up and take it out camping, off-road, on trips.

I wanted a slightly bigger tire without changing over to 33+ setup. The compromise was Toyo AT3 which comes in at exactly 32” inflated. (Had to do the pinch weld mod)
Great tire, lighter than LT and almost same footprint/contact with higher load capacity than the 15’s.

I did the cold tire “chalk” test to find tire pressure for the new larger softer tires. Actually, tip: what works well is get two pieces of plywood and some white poster board/paper, lay them down and roll/drive over them with the white poster board/paper. Bingo ! you get a perfect imprint of the tire on the flat surface of the paper, no chalk or paint necessary, the black rubber of the tire tread imprints the paper like a rubber stamp !

Results:
I found 31psi in the front tires to give a perfect imprint across the tire width tread ground contact. More than this starts to slightly crown and edges start to show slight less imprint. In the rear **(with a completely empty bed) I found 29psi to give the exact same imprint as the front, full width tread contact.
The ride quality seems comfortable and solid around town on pavement.

I understand that once it has weight in the truck and the tire heat up this changes the pressure, however, I do take it on the highway when the bed is empty. So the rig is very lightweight.

Should I inflate the rears more than 29psi for higher speed highway driving ? even if the bed is empty ? The max pressure on these are 44psi so I imagine 29 is not too low but I prefer even tire wear and good ground contact.

Thx !

 

I think you're probably about dead on. I have the same sized tires, but they're K02s (Load Range E), and doing the chalk test came out with 30/28 psi (front/rear). Tread wear has been very consistent and even and I like the way the truck rides (which is generally unladen, with no significant weight add-ons like numbers, racks, camper shell, etc), but I also do occasionally load it it quite heavy for camping/hunting trips.

 

I run fr @31, rear 29 as well. Empty. 265 75 15

 

Chalk test