These SRW trucks come with various spring rates in 400lb(?) increments up to 6k. Ford doesn't change the suggested PSI on the front for whatever reason. 60 seems to be that magic number. A gas 2wd 250 can show the same front PSI as a 4wd SRW diesel 350. It is what it is. Adjust as you like.

 

As others stated probably for tire wear and the handling probably goes to hell. Especially with a load on it.

 

I’m going down this rabbit hole myself. I just weighed my truck and looking at PSI numbers to try and figure this out. So, the truck is rated at 11,500 with 60/80 psi. While the sticker recommends 60 psi for the front, the steer axle weight is 5520. If I max out the rear and run the recommended 80psi, thats 5980. So a 20psi difference for 460 pounds does not seem right and that maybe I should be running the fronts closer to 70-75psi. Still need to do some more reading to try and figure out the best option.

 

You can figure out pretty much exactly what you need and adjust using the load chart inflation tables for your tire, probably a 126 load tire. I run more pressure than I need to in my 129 rated tires for my loads but that is still FAR less than what the sticker based on the original 123 rated tires which is 70/80.

 

For fun I aired my fronts up to the placard recommended 60 psi and the front end definitely felt more loose going down the highway. My rears call for 65 but I usually run them around 58. I think I'm going to bleed out my fronts to 55 and see how it rolls.

 

You know how it's bad to run a passenger side tire lower than a driver side tire because it'll wear out the spider gears faster? Imagine if the fronts and rears are very different and you switch to 4-high on a snowy day. That's why I try to keep all 4 of my tires somewhat similar in pressure.

My GWVR is 10k. What I've been doing is dropping my pressures weekly until I find that good compromise between wear and safety and comfort. This week I'm at 55 front and 52 rear. It's getting better. I probably could go lower but then the stupid TPMS light will come on the dash.

Something else I've noticed: On these trucks the tires heat up FAST. This is evidenced by the fact that when not hauling and not towing with ambient temp at 32F I still see my tires gain 5-8 PSI on a simple drive down the road at 45 MPH. I can only imagine that during summer when it's hot and the pavement is hotter, the tires would gain even more PSI while driving. Point is, if you set the tires to 60 PSI "cold" or ambient, then you may see them at 70 PSI during a highway trip, or more when towing.

I think the recommended tire pressures are WAY too high for a truck that isn't hauling substantial weight.

 

You've got the Powerstroke; so your front end is even heavier than mine is. I'll air myself down to 55 all around to see how we do.

 

After 30+ years and well over a million miles driven in F250 & F350 trucks my tires are always 65psi +/- front and rear unless I was running loads of scrap into the scrapyard then they would get aired up to 80psi for the run.

Always got 50k miles wear atleast from the tires.

Never felt any truck road horribly but then alway have weight in the truck and used it as a truck not a car.

 

Yep, my question was for those of us that run unladen. If it weren't for my RV hobby I'd be riding around in a F150.

 

Definitely different with the diesel up front. recent scale ticket for a diesel with a big steel front bumper was 5500 lbs. My 7.3 truck is a couple hundred less than that with a 900 lb snowplow cantilevered out the front end. My truck is about 3900 on the front 2900 on the rear when empty. No need for the crazy high pressures. I still have headroom at 55 psi with the plow fitted and could safely carry another 2000 lbs in the bed above the 800 already there.

Do consult the load charts and do the math. I like to leave that headroom in case I need to haul something unexpectedly. Otherwise I air up the rears if towing heavy, etc.

 

Even my dually which is basically unladen other than misc stuff in tool box, 1 5 gallon jug dsl, 1 5 gallon jug gas, 30lb and 20lb propane, 5th wheel hitch. Runs 65psi alround and it's the wifes daily driver if needed and pulls the 5th wheel.



Weight when driven from dealer lot.



I would like to see a blind test of tires aired at various levels in these trucks and guys tell the difference of ride quality. There is a test for TFL to do.

 

So, if I get this right. And if not, please tell me it doesn’t work that way I’ve been up since 3 so who knows.

Tire is rated for a max weight of 3750 at 80psi
3750/80 = 46.87 pounds per psi
As the weight is divided between two tires, In order to support a steer weight of 5520, I need a minimum of 59psi in each tire (5530.66) and then adjust up as needed before reaching signs of over inflation. Probably just going to leave them at 60 where they are now.

My current drive axle weight is 3560. So, theoretically, I could run the rear tires at a minimum of 38psi (3562.12). Now, any added weight would require raising psi so if say they are left at 50psi, that would accommodate roughly an additional 1124.88 pounds in the bed without needing to add additional air to the rear tires. Anything beyond that would be added until I max out at 5980 (truck is 11,500 max) or 64psi (5999.36). So maybe 65 or 66 max in rear.

Does this backasswords math make any sense?

 

All of these are the manufacturers CYA stickers from the 90's Firestone/Explorer rollover mess and lazy people never checking their tire pressures, sue happy litigation era... before then folks took responsibility for their actions or lack thereof when something happened, back then if you spilled hot coffee on you it was your fault, now it's somebody else's fault for giving you the hot coffee to spill... the tire pressure stickers are the same thing as the "Warning Hot Liquid" on Mcd's coffee cups... CYA (Cover Your A$$)

Personally, I adjust all my trucks tire pressures depending on what I'm doing with it.. my 77 F250 I use for wheeling and wood cutting, when going up in the high country I drop the fronts to 25 and rr to 15-20, sometimes lower, when cutting wood the fronts are 30 and rr 50, my 02 F350 I run the DRW's most the time at 50 (empty), fronts 60 and bump the rr up to 65+ depending on load. The stickers are there so the manufacturer can go "welp, not our fault, it says right there they should've had the tires at XX psi" in the case of an accident.

Most drivers (I said MOST, not all) these days are oblivious to their vehicle, they push a button and go, never checking anything, relying on all the electronic nannies to tell them if something is wrong, daily/weekly/monthly checks of your vehicle is a thing of the past many never do in a year, much less once a month.