Air pressure question

[stetch]

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

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[615_Bronco]

Higher pressure usually means you gain mpg but lose ride quality

 

[userdude]

I understand they overinflate the tires pre-delivery so they don't get flat spots. Not really meant to be driven that high (I would probably top out at 42psi for maybe a long trip prioritizing gas mileage), the make ready they're supposed to lower (I thought). 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.

Most people are doing 35-40psi. Higher psi = better gas mileage but bumpier ride. The inverse is true the lower you go. I'm usually 35-37psi for running around town; 35psi is noticeably softer than 40psi for me, both GY's and my M/T's. You can also do a chalk test if you want the best tread match to the road. This is all somewhat tire dependent, but some folks do 28 or 30 or 32 to get the most traction on road, but your gas mileage is going to suffer.

 

[Brian_B]

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.

 

[userdude]

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.

Another one is ambient outdoor temps. Colder air means lower psi, warmer means higher. If someone lives somewhere where the temps don't fluctuate a lot, not a big deal, but it's not uncommon in Texas for temps to fluctuate up to 40-50degs in a day (even seen 60deg). This is a big reason I don't go super lower (really below 32-34psi cold). Running around town on 22 or 47psi just feels wrong, even if it's just for the morning or afternoon. lol

 

[Thor_1]

36 cold so about 38-39 after driving a bit.

 

[Thor_1]

most 2-doors at 39 and 4-doors at 35 on the sticker

4 door heritage and the sticker pressure is 39. Wanted to verify.

 

[Brian_B]

4 door heritage and the sticker pressure is 39. Wanted to verify.

I think SAS goes 39 regardless of minivan status - but can't confirm.

 

[Notmattwong]

2-door base Sasquatch, I run 35 cold all around. It warms up to 38-39 on really hot Texas days. Averaging 20-21 mpg. They were all at 40ish when I drove it off the lot and highway speeds got the tires up to 44-45 psi which was really stiff.

 

[GoHawks63]

I run 36 psi when cold, which means they usually rise to around 39 psi after I've been driving for a while.

 

[Returntothefog]

4Dr Heritage w SAS, I run them on road at 33-35 cold, I think the recommended 39 rides a little unnecessarily rough and the gain in mpg is negligible

 

[615_Bronco]

I think SAS goes 39 regardless of minivan status - but can't confirm.

They do

 

[userdude]

I think SAS goes 39 regardless of minivan status - but can't confirm.

It's not a minivan, it's a stretch 2dr with egress attachments... lol

 

[MEDISN]

I chalked my Wildtrak SAS on factory Goodyears without the roof on (90% of the year in SoCal) and it worked out to 36psi front, and 34psi rear to give an even print across the contact patch. I leave it that way with the roof on too. I do have a steel cargo cover and tools in the back. Not sure what it would be empty. Never checked.

Allows for really smooth ride - eats up bumps and cracks in our lousy SoCal roads. Fuel economy remains 38 smiles per gallon with the 2.7L and Ford ProCal tune.

 

[MilesTeg]

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

My tires from the factory (ordered my Bronco) were way over inflated too. Must be something they do.

I ran 39 on streets for a while, per the door jam. However, it was wearing my tires pretty badly in the center (almost 2x the wear of the outside after 5k) indicating that 39 is too much inflation. I dropped it to 35, which seemed to stop the center from wearing faster. To try to even out the treadwear, I am setting it to 32 for a few thousand miles before I go back to trying to find the optimal pressure. All this is complicated a bit by having a 5 tire rotation, hah!

My 2DR 7MT Badlands still gets over 20 even at 75 (22ish at 65) with 35 psi, but haven't clocked it with 32 yet.

The door jam is only a guideline. You have to watch tread wear and adjust, just like I am doing. I should have watched it more carefully (like every 2-3k miles instead of waiting till 5). Then I wouldn't be juggling pressures so much.

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