Ok so we all know that the the recommended tire pressure for an F-250/350 is 65 psi front and 80 rear. I am running 325/65R18 BFG All Terrains and their max psi rating is 65 psi. I don't haul or tow, but I do a lot of highway driving. I have all 4 tires set at 60 psi. Does that sound like a good pressure for unloaded highway driving?

 

no as your tpms is probably going off. I think what I would do is air to max. But then I am always towing or hauling.

 

Aired to the max, unloaded can make for a stiff ride. You will get the most MPG but you will feel it. I usually run 65 all around and add pressure as needed if I am loaded. I wouldn't ever go below the recommended pressure though. The lower you go, the more and more heat that tire will create. This adds to a much shorter lifespan.

 

Air up to 65 or max psi in each tire.

If your trying to achieve even wear across your tires and maxium tire contact to the pavement, take a piece of wide kid's chalk and draw a straight line across the tread of each tire. Next, drive slowly in a straight line for about 50 yards or so. Do not turn the steering wheel. Keep the steering wheel absolutely straight. Without backing up, get out and evaluate the wear of the chalk. You will probably see the chalk has worn off in the center of the tire but some remains on each edge. Reduce the air pressure in each tire until you get uniform chalk wear across the tread.. You want to maintain the highest psi you can while having uniform wear. With TPMS, you might not be able to go below 50psi. On my 2010 with factory 20s (Goodyear AT/S, I believe I have mine set to 60psi in front and 50psi rear. I probably need to revisit this but I was afraid to go less than 50psi right before a road trip and set off the the TPMS light.

I hope this helps.