Air pressure question

[MilesTeg]

2-Doors tend to run about 3-5 psi higher than 4-doors from what I've seen, with most 2-doors at 39 and 4-doors at 35 on the sticker. Also note there is a difference between cold and hot pressures on a tire, and that can vary by 2-5 psi, and it can change a bit with altitude as well.

That said, look up something called "Chalk Testing" - it's super simple to do, and optimizes your tire pressure for tire longevity (not fuel economy). Just need a piece of sidewalk chalk and a little stretch of flat pavement. On my larger tires, chalk test showed 28 cold, but I run them at 30 on the street - a compromise between a more comfortable ride / tire life and fuel economy.

You can also use Forscan to adjust when the low tire pressure warning comes on, if you care to adjust that as well.

I should really do a chalk test.

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[stetch]

Thanks everyone, I need to do some deflating. I still have under 1k miles, so still figuring this out. Crazy how overinflated they gave me the rig knowing I had a 300+ mile drive home

 

[AZ_Liberty]

I think Ford also errs higher (39psi) due to the Firestone/Explorer issue they had in the 90's when they recommended lower psi and it proved dangerous.

People like to blame the lower pressure on the door sticker, but mine were inflated to 35 PSI and threw off the tread in less than 1000 miles. Those tires were defective. Period.

That being said, Ford does overinflate for shipping. Part of PDI is to take the air pressure back to the door sticker, so if OP had high pressure leaving the lot, that's on the dealer.

 

[Nibroc99]

2-Doors tend to run about 3-5 psi higher than 4-doors from what I've seen, with most 2-doors at 39 and 4-doors at 35 on the sticker. Also note there is a difference between cold and hot pressures on a tire, and that can vary by 2-5 psi, and it can change a bit with altitude as well.

That said, look up something called "Chalk Testing" - it's super simple to do, and optimizes your tire pressure for tire longevity (not fuel economy). Just need a piece of sidewalk chalk and a little stretch of flat pavement. On my larger tires, chalk test showed 28 cold, but I run them at 30 on the street - a compromise between a more comfortable ride / tire life and fuel economy.

You can also use Forscan to adjust when the low tire pressure warning comes on, if you care to adjust that as well.

My 4-door sildtrak (sasquatch) is 39psi on the door sticker, fyi. Must depend on if it's sas or not.

 

[userdude]

People like to blame the lower pressure on the door sticker, but mine were inflated to 35 PSI and threw off the tread in less than 1000 miles. Those tires were defective. Period.

That being said, Ford does overinflate for shipping. Part of PDI is to take the air pressure back to the door sticker, so if OP had high pressure leaving the lot, that's on the dealer.

No doubt the tires were defective. Did a too-low psi force the issue for many? I guess that's what the lawyers would say. I dunno, I still prefer not to go too low. YMMV.

 

[mrjking2000]

28 psi on 37s unloaded (verified by chalk). 30-32 fully loaded.

 

[AZ_Liberty]

No doubt the tires were defective. Did a too-low psi force the issue for many? I guess that's what the lawyers would say. I dunno, I still prefer not to go too low. YMMV.

And I'm still mad that those bastards at Firestone still owe me a set of tires. They only recalled the Wilderness A/T. The Wilderness H/T had the same defect.

Fortunately I was in my driveway and not the freeway when the tread chunked off.

 

[MilesTeg]

People like to blame the lower pressure on the door sticker, but mine were inflated to 35 PSI and threw off the tread in less than 1000 miles. Those tires were defective. Period.

I bought my Explorer only a little bit after that debacle. I (affectionately) named it the Exploder. I also was denied a uhaul rental even though my Explorer was a different model year and different tires than the affected models, hah.

 

[AZ_Liberty]

I bought my Explorer only a little bit after that debacle. I (affectionately) named it the Exploder. I also was denied a uhaul rental even though my Explorer was a different model year and different tires than the affected models, hah.

They used the same defective tires on the Ranger, but Ranger never got the negative press that the Exploder did.

 

[Kevin Scarbel]

So when I got my bronco a month or more ago, the tires were at 48-50psi. Which I remember as it was an absolutely insane psi.

Later. I aired down to 22 for some trails. I reaired to 43 before I got towed back to ford because of a fuel pump failure.

I asked them to complete the air up before I picked up my bronco. They said it was within spec.

So I look at the sticker in the door and it says 39, so technically I am still too high in psi.

The drive feel was very different at the high psi as you can imagine.

What psi do you use on the road? Clearly these tires do not seem to care how much air is in them. Want a good ride and gas mileage. I got 19mpg coming home from the dealer on the freeway, going over one mountain range and up another to where I live.

I seem to get closer to 15mpg with the lower pressure

I run SAS Broncos at 39 psi, per Ford and their door spec decal. I find my Goodyear MTs perform well at 39 (I air down for the beach).
I check tires when they're cold, e.g. in the morning.
I air down in the summer to offset the higher pressure that hot temperatures create, and air up for winter because air pressure drops.

 

[615_Bronco]

I bought my Explorer only a little bit after that debacle. I (affectionately) named it the Exploder. I also was denied a uhaul rental even though my Explorer was a different model year and different tires than the affected models, hah.

To this day I still call them Exploders, old and new.

 

[DALOLA]

I've settled in on 34psi for my OEM 35" GY's, for road trips. It's a good all-around compromise. The OEM GY's seem to be sensitive to slight PSI adjustments, so to dial in your particular configuration, I would test drive at 1psi increments. Time consuming, yes, but it will give you the best result.

 

[kojak8]

I do 26psi. 25 outerbanks sas. Rides better than my Cadillac

 

[BillyB]

My Q: is the TP Instrument display accurate???
Also...FWIW...

 

[psdtime]

I run 30-32 psi on stock 35" SAS tires. Used Forscan to change TPMS to 32psi.

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