Here's a refference for you. Just looked up my tires.
BFG KO2 in 35X12.50R17 E rated tires.
PSI 25 30 35 40 45 50 55 60 65
Weight 1875 2155 2405 2625 2840 3000 3065 3130 3195
per tire
So as you can see, if I run the tires at 65PSI as per the truck sticker, I need to be carrying around 12,000 lbs total, truck and all.
With mine set at 40 front, 35 rear, I'm still a little heavy at 10,060lb. But my truck only weights about 7000 empty, So I probably need to lower them some more. at 7500 lbs running weight, I could go all the way down to 25 PSI, But I don't think the wear pattern would be right. SO I may just go down to 35/30 and see.
Tires are part of the suspension. SO if you have them pumped up to max PSI, the truck will ride harsher as the tires are stiffer/wont flex. Lower the tire pressure to the weight you are running and you will get a better ride quality. Just remember to inflate them when you put in a heavy load/pull a trailer.
I trust the BFG engineers to know what they are doing. BFG is our tire sponsor on our Baja race truck and I see them out at the races all the time checking everything from tire pressures, temps, to ground temps, dew points etc.