...and I have a question about pressure. It's a 2001 F250 CCSB Lariat 4x4 with 6.8 and 55K. I just put a new set of BFG All Terrain LT 265/75R16 on the truck. I don't haul anything to speak of and am wondering what a good all around tire pressure to run would be. I've looked around trying to find an answer and it seems to elude me. I'm used to 1/2 ton trucks and this is my first experience with a bigger truck and this type of tire/tire pressure. Any advise would be appreciated. Thanks all.

 

Inside the gas fill door, there should be a sticker recommending pressures. I believe it is 45 psi up front and 70 in the rear. If you don't haul anything, you could do 45 in all corners. It all depends on the tire. I have General Grabber AT2s which are a similar tire. The installer only filled them to 35 which was WAY to low. You could see them bulging at the road contact. I have all four at 60 psi right now the ride nice but are pretty firm. I may drop them down to 50 psi when I rotate them next.

On a different note, the previous set of tires were highway tires... Transforce HT. They were maxed out at 80 psi. They rolled really smooth and got great fuel economy. They were a lot thinner wall than my current tires though.

Its all trial and error. See how they ride. Look for the bulge at the contact point on the road. Watch how the wear. Over inflated tires wear the center of the tread and under inflated wear the outer edges.

 

No, it's not guessing at all. Simple math can be used.

Put your truck on a scale and get the axle weights. Divide the axle weight in half, then that by the load rating of the tire, and call that percentage of the max sidewall pressure your minimum pressure to run safely. You can adjust upwards from there, but that is the minimum safe pressure to run.

(Pressure / Max Sidewall Pressure) = (Actual Load / Max Tire Load)
Solve for Pressure to find your minimum for what your truck weighs, you'll know the other three variables from the tire sidewall and your weight receipt.


Example based on my truck:
( X / 80 ) = ( 2000 / 3195 )
X = 51.8psi

(2000# is a rough guess from memory, my last scale ticket was ~8200# and I don't recall the axle weight split)

 

The rep gun is out of ammo, but thank you. I have never seen that calc before. Using the rough numbers my tires should be at 42 psi when I am empty. It does make complete sense though, just never put the maths together.

 

And I'd agree that above the minimum you can do pretty well as you please. I ran my stock tires at a full 80psi and didn't see any abnormal wear and didn't feel the ride suffered much. But when i had ~35" MT tires I ran them at just over half pressure and they still crowned in the middle. They were rated to 4080# each though.

 

Personally, I do not run mine below 50 psi. although the tire guy said to put in 45 psi to avoid a rough ride. I'm usually run between 50 and 55 psi and that suits me just right. I always up the pressures when carrying a load.

When I max load it with our Truck Camper and 300 lb. tongue weight trailer, I go 80 psi in the rear and 65 psi in the front. That seems to work really well too.

 

Thanks for the replies. This helps a bunch.

 

Interesting that I keep seeing talk about getting a soft /smooth ride in truck. I would think that if you buy a truck you know your going to get a truck ride and not a sedan smooshy ride.
I have General Grabbers and run them at 70+ full time and 80 when towing. The ride is stiff but, after all, it is a truck.

 

For a better ride ditch the solid front axle and go to a ifs system.

 

Like ssunit1 when I want a comfortable ride I take the wife's Honda. For playing around I take my Bronco. To work the F250.
I grew up in northwest Arkansas in the 60s and 70s and understood trucks were for working and they all rode bad even the 100s. I can say my last 2 F250s ride tons better than my first A 74 D 100.
That being said can ride be improved yes but load suffers and I go down the road right at 20,000 lbs.
I run 60 front and rear unloaded and max sidewall loaded and typically get 50K from my 40k tires, my Toyos have 45k so I'm changing them when I get back. I gotta keep it simple. It's not rocket science. And with my job and all the numbers I keep track those are ones that work best for me.

 

For me it's not really about trying to get the ride smoother, it's about keeping the tread wear even. When I know I'm not going to be pulling or hauling, I'll air my tires down to 60-65, but when I'm pulling or hauling, then it's 70 front and 80 rear.

Just had my tires rotated (they only charge me $20 to do it) with my "free" oil change at the dealer, and the kid aired them all up to 80 all the way around again. Sigh. That's too much pressure for unloaded driving, the outer edges of the tread don't touch the ground. Had to go out and air them down again.

 

hmm, my sticker says: 65PSI cold front and rear. Why such parity between model years?

 

No idea. My sticker says 75 front, 80 rear. Photobucket is taking a dump right now, so can't link the pic.

There it went, site working again...

 

Do you have 18" wheels?

17" tires are usually a max load index of 121, or 3,197#. An 18" tire with a load index of 125 is rated to 3,640#. To cover the same RGAWR of an F250, the 18" tires don't require as high a pressure based on the math above.

An F350 SRW with 18" tires will have a higher inflation pressure than an F250 because the F350 has a higher RGAWR and GVWR.

This is also why an F350 SRW with 17" tires have a lower RGAWR than if it came with 18" tires, the max load capacity of the smaller tires won't add up to 7100#, it takes the higher load index of the 18" tires to get there. There used to be a de-rating package that was forced to be selected on commercial truck builds of F350 SRWs with 17" tires, pre-2017.

That load rating sticker is also based on tire pressure to carry the max rated load, if you're empty then you can weigh the truck and figure out what your true "empty" minimum pressure is.