I run the 315/75/16 BFG all terrains in the load range D. I run the fronts at 55psi and the rear at 48psi. When I tow I bump the rear up to 55psi also. You never stated if you have load range D or E? I think the door sticker is pretty much worthless when it comes to aftermarket size and type of tires. Every tire manafacturer has diffe're rent specs, just like every truck maker does. You just have to pay attention to tire wear, but if you are under-inflated, you're asking for trouble! I have gotten 40-45,000 miles out of two different sets of BFG's running them at these pressures.

 

I agree with you UP_There, you have to pay attention to the look and feel as well as tire wear to target an inflation pressure. We cannot blame Ford here. The fact is that a single tire pressure cannot be correct for all vehicle loading situations. It's just physics. I have seen charts where the correct pressure for a given load on a tire was given (that's where weighing your axles becomes important) but I don't see that on the BFG site now. It seems like they think we are best treated like mushrooms and kept guessing.

Bill

 

Maybe I am not understanding how this works but let me try to explain what my understanding of tire information is:
1: There is no way the manufacturer of the truck can tell you what tire pressure you should run as tire types and compounds vary greatly. ie: sticker on the door is useless.

2: On E load rated tires it gives you the "max load" at 80 psi. This means the NORMAL tire pressure for this tire is 80 psi.

3: If you inflate to anything less you are underinflating the tire. All of us know what underinflating a tire can cause. (sidewall roll, loss of control, heat, etc...)

I may be wrong but I have not read anywhere in technical docs that seriously says "run it where you feel the ride is best"

Just my .02

 

Well, I don't think you will get a consensus here, or anywhere for that matter. I think some of us are explaining what we do.

>1: There is no way the manufacturer of the truck can tell you what tire >pressure you should run as tire types and compounds vary greatly. ie: sticker >on the door is useless.

Well, not useless, but maybe not ideal. If you want to run a pressure that is safe for any load, right up to the GVWR of the truck, then run the door pressure. It will ride rough, it will wear the center of the tread, but you won't have to ever worry about being underinflated which would be the worst possible thing.

>2: On E load rated tires it gives you the "max load" at 80 psi. This means the >NORMAL tire pressure for this tire is 80 psi.

Not necessarily normal. That's the point, normal is the correct pressure for a given weight upon a tire. Given that that correct pressure might be different every day, Ford tells you that normal is inflated high enough to handle the GVWR.

>3: If you inflate to anything less you are underinflating the tire. All of us >know what underinflating a tire can cause. (sidewall roll, loss of control, >heat, etc...)

I think we can all agree that underinflating for a given load on a tire is dangerous, so error on the side of over inflation, but never more that what is printed on the tire side wall.

>I may be wrong but I have not read anywhere in technical docs that >seriously says "run it where you feel the ride is best"

Really? Have you never seen the recommendation for chalking across your tread and driving a short distance and see how the chalk has worn? Isn't that in fact a recommendation for doing something other than the door sticker? That a pretty standard test, although I don't think it is as good with todays radials as it once was.

 

BTW, there is a forum down the list dedicated to tires. I don't hang out there but it's probably a good source of information about inflation and how it affects handling.

Bill

 

Goodyear has charts online that show correct inflation pressures for varying loads on their tires, by size, and also information about how speed affects the ratings.

http://www.goodyear.com/truck/pdf/da...dInflation.pdf

I don't know if BFG has such a thing online but I would bet that it exists somewhere for the truly inquiring minds. Some extrapolation could be done using the Goodyear data for tires with similar maximum load and pressure ratings and get you fairly close.

Bill

 

I run 35 front and rear unloaded and have never had any issues with wear or anything else. If I tow I bumper them up to the max pressure listed on the tire.

 

My 2008 F-450 dually says 80psi front and 75psi rear. Sounds like that should be reversed?
Oh well

 

The diesel requires higher air pressure in the front because of the weight of the engine.

 

toa5150medic -

I have your same tires in the same size. Mine say load range D on the sidewall and max 50psi cold. I wouldn't *ever* go higher than the tire mfgr recommends.