Question about tire pressure

jadatis wrote:

MG1912 wrote:
My 2007 Ford F350 6.0 supercab long bed SRW has Nitto Terra Grappler G2 A/T LT295/70R18 E 129/126Q tires front and rear. The truck came with 275/70R18 LRE tires, which were replaced by the previous owner. I wrote to Nitto to ask them about recommended tire pressures for my truck camper application (~3,000 on front axle and ~7,000 on the rear axle). I received what seemed to me like a lawyerly response:

"Based on the information provided, the calculated pressure for your Terra Grappler G2 tires is 65 PSI cold pressure on the front tires and 68 PSI cold pressure on the rear tires. At these inflation pressures, your tires are supporting the same amount of weight as your OEM tires did per the vehicle manufacturer's specifications. For any increase in pressure due to towing, we would recommend referring to your vehicle owner's manual for any instructions."

I was surprised because I would have thought they'd recommend closer to 80 PSI for the rear tires. Is their response cautious due to liability concerns? The reference to OEM tires and the vehicle owner's manual makes me suspect this. Or do the recommended pressures sound right?

My advice with these given weights is F 39 PSI and R 52 psi, but disclamer is that your given weihts are right. And that is the most tricky part in it all . So also this is a lawyery advice.

Added 10% to axlelloads, and lowered the maxload a tire by 20%/ 8 LI-steps, because offroadkind, with probably large profileblocks that cover part op sidewal.
Assumed rear Dualload axle so 4 tires behind.

This is for highway use up to 99mph, if the car can do that speed.So maximum reserve with still acceptable comfort and gripp.

For in SandMud and ontrack it can be much lower.

Edit: assumed axlelweights to be F 3000 R 7000, or where they axle-ends weights? Then 82F and 103 rear.

Holy cripes, this post is a bigger train wreck than Kaytegs....
1. Front axle weight is nowhere near 3000lbs on the front of a diesel F350. Replace the 3 with a 5 and you'll be close.
2. 7000lb on the rear is probably close with that truck and camper. +/- 500lbs anyway.
3. 39/52 psi is WRONG like wearing your underwear outside your pants wrong...
4. 82/103 psi is actually more wrong than the first guess.
5. However if you average BOTH of your recommendations, somehow that is just about right. Maybe coincidence, maybe genius, I don't know.