I'm running the nitto grappler g2 325/65/18 and when I checked the tire pressure after they were installed it is 42 psi. The nitto website indicates it should be 65 psi. The truck is a second vehicle and I only put about 500 miles a month on it. My question is should it be 65 psi or is the 42 psi good?

 

i run 38 psi all season.. 65 psi will give u a really harash ride i believe..

 

Same tires, same size on our new to us 06 f350 super crew long bed powerstroke. I'm running 50psi in them. I mounted and balanced them. But I was thinking about dropping the pressure a tad. It rides nice now. It is stiff but that's just the suspension on the f350.

 

Best way to determine the pressure is the chauk test.

 

F350 is a totally different beast... weighs alot more too.. i think u need a minimum of 50 psi to keep tpms light out

 

I run 42 psi in my 325/65/18 Falkens.

 

Thank you everyone for the info...

 

This.

Go buy yourself a set of crayola driveway chaulk from walmart for $0.97 and find a flat parking lot and spend 15 minutes of your time to get the pressure right.

By the way, my 305/55R20 Nitto's settled in at 46psi front, 38psi rear, using the chalk test. That means the entire width of the tire is making contact with the road and neither is over or under inflated. (trucks are always heavier in the front, and, I would need to up the rear tire pressure if I haul a heavy load, you know, if I wanted to be precise)

And my mpg went up 2mpg, and truck rides really great, and my tire wear will be even.

That 65psi or whatever is likely the MAX psi. To my knowledge the only psi that all tire manufacturers post is the max psi for the tire. Unless you're hauling a few thousand pounds of load every day, that is way too much.

 

One other important item to remember: the valve/valve stem. Most valve/valve stems are rated at around 35 to 40 PSI (the black rubber ones). If you put more air into your tires (if they are rated for this) for reasons such has towing or hauling heavy loads, then you want to make sure the valve/valve stems are rated for higher tire pressures. The metal/copper tubed valve stems are rated for this. The black, lower pressure valve/valve stems can and will leak, and can blow out of the rim if you inflate higher then the valve/valve stems are rated for.

Discuss this with your tire shop whenever buying tires for your truck.