Questions about tire psi

ShaneC

Tremor Fan
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PA
Current Ride
2015 F150 Platinum
Hopefully you guys can school me a bit on what the optimal psi is for the tires. Seen a few posts regarding people running their tires at different psi, and was wondering what would work for my needs.

What I would like to gain is a bit of ride comfort and gas mileage. Most of this trucks life will be local or long distance highway, most of the time with just a payload in the bed, although I do tow on the turnpike intermittently. If any of y’all have any tips would be greatly appreciated!
 
people that actually have their trucks can give you specific numbers, but in general higher psi will yield better fuel economy and a rougher ride, and vice versa. If you’re gonna go below the recommended psi, the sweet spot is pretty much up to you.
 
people that actually have their trucks can give you specific numbers, but in general higher psi will yield better fuel economy and a rougher ride, and vice versa. If you’re gonna go below the recommended psi, the sweet spot is pretty much up to you.
Gotcha, yeah haven’t really considered messing with it until now. Had a f150 plat that had a smooth ride and am driving a 6.2 f250 right now that isent exactly smooth haha. Not that I mind the rougher ride though, just figured if I could change something to make it ride smoother that would be nice.
 
I am at ~50psi all around right now. Ride is definitely improved from the 60/70 factory pressure. Too early to tell regarding fuel economy since I have only had my truck a few months and only made two highway trips. Agree with @Mojave_Idiot though that I would not expect it to improve, just hoping for minimal loss...
 
I am at ~50psi all around right now. Ride is definitely improved from the 60/70 factory pressure. Too early to tell regarding fuel economy since I have only had my truck a few months and only made two highway trips. Agree with @Mojave_Idiot though that I would not expect it to improve, just hoping for minimal loss...
Once I get my truck I will give it a try…… Definitely wouldn’t mind playing with it but wanted to see what others have done so I have a base to start at.
 
So I decided to experiment. I've been running F and R in low 60s. Raised R to 73 and F to 63 and went for a 60 mile drive. Felt a little stiffer back there but not bad. Didn't feel quite as planted as with both in low 60s but then I was doing 75-80. I might keep it there as it figures mileage will be better and tire life should also improve. It's kind of pointless though since I tow over 90% of the time. Next tow I will go 67F and 75 R. Stay tuned! 🤡
 
For a different approach to it, here’s a weight capacity chart for the factory tires at different PSI’s that’s been shared before. Can use this to fine-tune your pressures based on the actual weight on the tires.

 
CCW, maybe I'm illiterate, or just more confused than usual, but I don't get that chart's 'Max Load'. Does it refer to payload or GVWR divided by four? If it is payload it implies that if we're empty we should be running 35psi? That's what I run in the sand!
 
CCW, maybe I'm illiterate, or just more confused than usual, but I don't get that chart's 'Max Load'. Does it refer to payload or GVWR divided by four? If it is payload it implies that if we're empty we should be running 35psi? That's what I run in the sand!

It’s the maximum weight rating of a single tire at a given pressure.

Your tires need to carry the weight the truck places on your rear axle, plus what your payload places on your rear axle, divided by two.

As such 65 psi in the rear will carry a load at the weight rating of the platform which is limited by other components.
 
CCW, maybe I'm illiterate, or just more confused than usual, but I don't get that chart's 'Max Load'. Does it refer to payload or GVWR divided by four? If it is payload it implies that if we're empty we should be running 35psi? That's what I run in the sand!

It’s the maximum weight rating of a single tire at a given pressure.

Your tires need to carry the weight the truck places on your rear axle, plus what your payload places on your rear axle, divided by two.

As such 65 psi in the rear will carry the weight rating of the platform which is limited by other components.
Was typing up a response, but Soop beat me to it. And nailed it. :D
 
The chart title says: "Corresponding tire load capacity"

It doesn't say front, rear, per axle, or whatever.
I need a plain English translation like - Curb weight + payload.
I think I can divide by four.

Aircraft weight ratings are simpler than pickup trucks'!
 
The chart title says: "Corresponding tire load capacity"

It doesn't say front, rear, per axle, or whatever.
I need a plain English translation like - Curb weight + payload.
I think I can divide by four.

Aircraft weight ratings are simpler than pickup trucks'!
The chart is looking at the tires individually, without any regard to the rest of the truck.

Simple formula:

Go to scale, get weight on each axle. For each axle, take measured weight and divide by two. That’s the weight each tire on that axle needs to carry. The appropriate pressure can then be looked up in the chart.

If you instead want a number that’s safe for everything, you can substitute in the GAWR for the measured weight, as that’s what the axle itself is rated for. Remember that front GAWR is less than rear GAWR with these trucks.

So for example (pulling numbers out of my arse here), let’s say you go to a scale and get a front axle weight of 4000 pounds and rear axle weight of 6000 pounds. Your front tires should be at a pressure corresponding to 2000 pounds and your rear tires at a pressure corresponding to 3000 pounds.

Looking at the chart, that means front tires at…well it bottoms out the chart, so 35 psi. The rears at 50 psi (personally I would go for 55 psi to add a bit of buffer).

In the case of my truck, front GAWR is 4800 pounds, rear GAWR is 6950 pounds. Using those numbers instead of measured weights gets me pressures that will support what the axle is rated for, and therefore what I should never exceed anyways.

In that case the front tires each need to support 2400 pounds and the rears 3475 each. Based on the chart, that works out to 40 psi up front and 65 psi in the rear.
 
tire life should also improve
This will only be true if you match load and pressure to achieve an optimum contact patch. If not, you will experience uneven wear which will reduce the overall tire life.
 
Following. I would like to know the best ride pressures F/R without having to make Forscan changes.
 
50f / 65r cold is the minimum without Forscan before your TPMS lights come on.

Run at that minimum.
I was at 50/60 for awhile with no warning but mine is an f250 so the factory setting is 60/70 (vs. 60/80 on F350)

Warning finally came on around 46 or 47 on the fronts once the temp dropped.
 
I was at 50/60 for awhile with no warning but mine is an f250 so the factory setting is 60/70 (vs. 60/80 on F350)

Warning finally came on around 46 or 47 on the fronts once the temp dropped.

It's possible they changed the minimum for 2022, but I'm pretty sure they didn't based on other reports here.

More likely a difference in instrument calibration and “cold air temp”.

“Cold” is typically defined as 65º–70° ambient temperature (68º is what I believe calibration temperature to be.)

Also: The TPMS sensor is somewhat erratic in behavior. It'll sometimes let you get away with far less than recommended pressure, and other times complain if you're a degree under 50/65 “cold”. I'm not sure what the logic is.
 
I was at 50/60 for awhile with no warning but mine is an f250 so the factory setting is 60/70 (vs. 60/80 on F350)

Warning finally came on around 46 or 47 on the fronts once the temp dropped.
Good to know. Mine is a 250 as well.
 
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