For those tires, you probably need to be running Max psi for the fronts at least. Do you know what these engines weigh?
no, he shouldnt. he should chalk test his tires to determine the pressure.
That being said, i also have D load tires, they say they can handle 3650 lbs at 50 psi. The sidewall is definitely soft.
They were the best 37" tire i could find..and was too cheap to pay the extra 100$ per tire for toyo MT 37" in load E...next time though.
I didnt like the way the sidewall looked when i had 2500 lbs in the bed on an 8k lb truck. Technically the tires could handle alot more..but it sure didnt look like it.
Getting back to chalk testing, unloaded I run 38 lbs front and 30 lbs rear. tire is a 37x12.5x17. The wider and bigger the tire, the less pressure it requires to support the same amount of weight due to its increased surface area.
OP..i still dont understand what you mean it feels like it "catching air: over every bump. Does it wander? When i go over washboard dirt roads quickly the truck is definitly floaty feeling. I blame my monroe magnum shocks. I dont think they cna handle the big tire and quick articulation. On a new fresh paved road, if it is a little wett and sun shines on it, you can see it has very small "washbaords" you cant feel it in a normal car. But my truck will go into a small shaking/bucking motion over this road, while normal cars sail by. i know it feels butter smooth in the Lexus.
Bilsteins next time..