Hey Gang,

So, I must be missing something here. I'm very familiar with tire load charts and weighing your vehicle; I've had many motorhomes in the past and this practice is crucial to having a rig that handles reasonably well w/o rattling your teeth out of your skull.

So ... naturally I look at my truck and assume the same principles apply. I read a lot on this forum how folks air down the *** end of the truck if they're riding unladen because there are thousands of pounds assumed on the placard that in many cases are not present in the truck. In my case, the truck is unladen until I hitch up a travel trailer and head out camping.

My door placard calls out, 60 PSI up front and 65 PSI in the back. 60 PSI up front on a LT275/70R18 tire is listed out as 3020 pounds. Which would mean my front axle would be able to handle 6040 lbs; however my FAWR is only 4400 lbs. 4400/2 = 2200, which according to the pressure charts can be handled by 40psi. Why would Ford put the PSI up to where the tire could handle so much more weight then you could ever expect to carry? Is it a mpg thing?

I've been staring at the charts and the door placard for over an hour now trying to figure out where my thought process is wrong. My RAWR is 6340 lbs, which equates to 3170 per tire and that lines up nicely with the 3195 pounds that 65 psi can take. The front makes no sense to me at all.

What am I missing?

 

You're on the right path. Its not one number fits all and rather a balancing act of load handling, fuel economy, tire wear, and vehicle handling. In a perfect world you'd weigh and adjust tire pressures every time you changed the loadout of the vehicle but hardly any of us are going to do that.

 

Right, but the front end will NEVER carry enough wait to warrant 60 psi, so I have to assume its a mpg or handling issue at that point?

 

Yes, dropping your psi according to the rated weight capacity will set you up for decreased fuel economy, softer steering, and uneven tire wear.

The same can be applied to the rear end at max psi with no load. Harsher ride and center of tires wear out faster. You can see finding your own balance as others do can benefit you over the one number on the placard.

 

So do most people run placard pressure on the fronts and play around w/ the rears?

 

Placard pressure is assuming you are at max GVWR of the truck at all times. My DRW is 60psi all around. Placard pressure is 80psi which is even overkill for the GVWR. I run 60psi towing or unloaded. When I ran the recommended 80PSI in my fronts on a DRW they always start cupping.

 

The front axle can go up to 6,000 capacity and they just leave the psi to cover that.

The rear axle is 6340 and they leave the psi to cover that.

I believe this is the case for all the tire types on all the F250 trucks.

 

The rear axle PSI just barely covers the RAWR. Which is fine b/c it covers it. The front PSI overshoots the max FAWR by ~1600 pounds. The point of my post was ‘why’?

 

Because running the tires at a low enough PSI to match the axle rating will reduce fuel economy and wear the tires out prematurely.

 

My guess is, as mentioned already, that they do it for handling balance. I think they are all no more than 10 psi difference front to back. I think they are all at least 60 psi front. Mine has the plow prep and came on the lightest tires, the 275/65-18 123 load rating. It has a placard at 70/80, which I never run.

I have the Tremor sized tire in a 129 load rating and in the summer I run 48 fr and 42r. One thing I noticed, especially with the tall sidewall tires at this psi is that it is a bit squirrely on initial heavy braking. not a big deal if you expect it but at 60 psi you likely are not experiencing this.

I guess I do not wonder why, doesn't matter because I set my own pressures. I get excellent fuel economy for a truck like this and I get excellent tire wear well below the placard ratings. I adjust for my loads as needed. For winter I am at 55 all around for the snow plow and ballast weight in the back.

 

Mine came with 60 in the front and 80 in the back and that's what the sticker says as well. When I'm not towing I run them at 50 front and 70 in the back for a little bit nicer of a ride. I tried going to 60-65 in the back but it sets off the TPMS so I'll stick with 50/70 when not towing. I run them at 60/80 when I am towing.

I keep it simple.

 

So, these newer trucks must be very different than my 2022, because my F250 has a front axle rating of 5000 pounds with the stock 265/70/18 tires at 60 psi.
And, my rear axle rating on those same tires is 6340 at 75 psi.
Now, I have upgraded tires to 275/70/18's, and run the fronts at 60 psi, and the rears at 70-72 psi, and these tires at 80 psi have a higher rating than the original 265 tires.
Truck GVWR is 10,000, obviously well below the axle ratings at the recommended tire size and inflation.

 

Yours is a 2wd so less front axle rating. I have a 2wd dually and will check it when I think of it.

 

Probably something to do with the front tires sagging some if they drop it.


You can adjust your tpms. I have some 127 rated tires that max at 65psi and I adjusted them way down to like 50 and it will cover my uses per the load chart I used (which doesn’t include hauling a gooseneck at this time).

 

2019 F250 4x4 6.2 and after upgrading to 295/70/18 Falken Wildpeak AT3W, I settled on 60 front 55 rear after performing a chalk test. I bump all tires up 10psi when towing my 31' TT.