Tire pressure

[Jrock]

MD set all the ties at about 44PSI. I have lowered to the door jam recommended 38, but was curios as to what you all run on the street and why? Also does the 38spi that’s recommended support the max payload capacity and if I wont typically be going anywhere near that level should I lower a bit further?

For full transparency, I go so excited when I got the truck I did 300 miles with the 44 PSI and the truck was still incredibly comfortable. I just deflated to 38, so not sure if I will be able to tell the difference on the seat of pants test.

 

[Jrock]

OK so no replies… I started messing around with ChatGPT to educate myself on factoring in PSI for load, towing/ off-roading . After prompt engineering for 10 minutes and giving it the data it required it came up with the following…

On all previous road vehicles I have owned, there hasn’t been a need for me to tweak PSI outside of what’s recommended, so this was learning process for me that may help others.

ChatGPT Created this cheat sheet based on the stock tires, with the details of how it arrived at these recommendations further below. (I=ChatGPT)

The on-road recommendations seem straight forward and accurate, I dont have any experience with serious off-roading so when I get some more time will have to verify the accuracy of those.

1. On-Road Tire Pressure Recommendations





How I determined PSI:


• Your tires are LT325/65R18D (Load Range D) with a Load Index of 121 (3,195 lbs per tire at 50 PSI).


• I used standardized LT-metric load/inflation tables (published by T&RA and manufacturers like Michelin, BFG, etc.) to correlate pressure with real-world load capacity.


• Your truck’s curb weight is 6,283 lbs, divided over four tires = ~1,570 lbs per tire when unloaded.





Why the PSI ranges:

Scenario​	PSI Range​	Why​
Unloaded Daily	34 PSI	Matches actual weight; smoother ride without risking underload wear.
Moderate Load	38 PSI	Manufacturer’s doorjamb recommendation; balances performance, safety, and fuel economy.
Heavy Load / Towing	40 / 44–46 PSI	Increases rear capacity for safe towing, per load tables.
Max Payload/Trailer	42–44 / 46–50 PSI	Approaching GVWR; tires need full inflation to hit 3,195 lbs each.

2. Off-Road Tire Pressure Recommendations





How I determined PSI:


• Based on experience from off-roaders, trail mechanics, and tire physics: lower PSI = more traction via increased surface contact and sidewall flex.


• Each terrain favors different characteristics—some need grip and articulation (rocks), others need flotation (sand).

Why the PSI ranges:

Terrain Type​	PSI Range​	Why​
Highway to Trailhead	34–38	Normal inflation is safest for paved roads.
Packed Dirt	26–30	Reduces jarring and improves traction on loose gravel and washboard surfaces.
Rock Crawling	18–22	Maximizes tire flex for grip on boulders, but risks de-beading without beadlocks.
Deep Sand / Dunes	12–16	Large contact patch prevents digging in; ultra-low pressure increases flotation.
Desert Running	22–28	Mix of traction, control, and heat management at speed.

3. Beadlock Recommendations

How I determined PSI cutoff:


• Based on common off-road best practices and failure cases from tire shops and 4x4 forums:


• Standard wheels rely on air pressure to keep the tire seated on the rim.


• Below 15 PSI, the bead begins to lose its grip—especially when turning or articulating.


• Below 10 PSI, you’re depending on luck and sidewall stiffness unless you have beadlocks.





Why the beadlock cutoff:

PSI​	Recommendation​
>15 PSI	Beadlocks optional
12–15 PSI	Beadlocks recommended for frequent use
<10 PSI	Beadlocks strongly recommended
<8 PSI	High risk of de-beading without beadlocks

 

[cconnorhtx]

This is really good info - thank you (and ChatGPT) for putting this together.

I'll target 35/36 psi in mine

 

[Cpl0724]

Damn, this is great, thanks!

 

[Cautionary Tale]

OK so no replies… I started messing around with ChatGPT to educate myself on factoring in PSI for load, towing/ off-roading . After prompt engineering for 10 minutes and giving it the data it required it came up with the following…

On all previous road vehicles I have owned, there hasn’t been a need for me to tweak PSI outside of what’s recommended, so this was learning process for me that may help others.

ChatGPT Created this cheat sheet based on the stock tires, with the details of how it arrived at these recommendations further below. (I=ChatGPT)

The on-road recommendations seem straight forward and accurate, I dont have any experience with serious off-roading so when I get some more time will have to verify the accuracy of those.


View attachment 9756

1. On-Road Tire Pressure Recommendations





How I determined PSI:


• Your tires are LT325/65R18D (Load Range D) with a Load Index of 121 (3,195 lbs per tire at 50 PSI).


• I used standardized LT-metric load/inflation tables (published by T&RA and manufacturers like Michelin, BFG, etc.) to correlate pressure with real-world load capacity.


• Your truck’s curb weight is 6,283 lbs, divided over four tires = ~1,570 lbs per tire when unloaded.





Why the PSI ranges:

Scenario​	PSI Range​	Why​
Unloaded Daily	34 PSI	Matches actual weight; smoother ride without risking underload wear.
Moderate Load	38 PSI	Manufacturer’s doorjamb recommendation; balances performance, safety, and fuel economy.
Heavy Load / Towing	40 / 44–46 PSI	Increases rear capacity for safe towing, per load tables.
Max Payload/Trailer	42–44 / 46–50 PSI	Approaching GVWR; tires need full inflation to hit 3,195 lbs each.

2. Off-Road Tire Pressure Recommendations





How I determined PSI:


• Based on experience from off-roaders, trail mechanics, and tire physics: lower PSI = more traction via increased surface contact and sidewall flex.


• Each terrain favors different characteristics—some need grip and articulation (rocks), others need flotation (sand).

Why the PSI ranges:

Terrain Type​	PSI Range​	Why​
Highway to Trailhead	34–38	Normal inflation is safest for paved roads.
Packed Dirt	26–30	Reduces jarring and improves traction on loose gravel and washboard surfaces.
Rock Crawling	18–22	Maximizes tire flex for grip on boulders, but risks de-beading without beadlocks.
Deep Sand / Dunes	12–16	Large contact patch prevents digging in; ultra-low pressure increases flotation.
Desert Running	22–28	Mix of traction, control, and heat management at speed.

3. Beadlock Recommendations

How I determined PSI cutoff:


• Based on common off-road best practices and failure cases from tire shops and 4x4 forums:


• Standard wheels rely on air pressure to keep the tire seated on the rim.


• Below 15 PSI, the bead begins to lose its grip—especially when turning or articulating.


• Below 10 PSI, you’re depending on luck and sidewall stiffness unless you have beadlocks.





Why the beadlock cutoff:

PSI​	Recommendation​
>15 PSI	Beadlocks optional
12–15 PSI	Beadlocks recommended for frequent use
<10 PSI	Beadlocks strongly recommended
<8 PSI	High risk of de-beading without beadlocks

Door Jam tire pressure is usually based of moderate average temperatures and cold tire pressure. The pressure will increase as you drive, and they warm by about 1 PSI per 10 degrees warmer. The pressure will also increase by about half a PSI for every 1k of elevation increased, or down half if descending.

All that being said, I have been at max GVWR and found 50 PSI cold in about 70 degrees works okay enough. I have tried chalking and marker on tires to check my wear patterns and just can't find anything that survives any significant amount of distance. I tend to go up in elevation by 6-8k so tire pressure is considerably higher when I get to destination. I use a morflate 4 way inflate/deflate to deflate down to 36 when on way to basecamps and once there (and mostly unloaded, except for fridge) I air down to 14 for off-roading. The trip I'm going on tomorrow, I might try 12 PSI as 14 is still a bit higher than I've liked. I have beadlock capable but haven't done the ring on them yet as I don't want an insurance issue or fix-it ticket.

Thus far I haven't had a CV or tire puncture, but I'll be sure to post about how well the trail repairs go. I keep the spare in stock location currently, though that's something I'd like to find a remedy for.

Been using those pressures in thick thick mud, snow, water, dirt, and rocks.

 

[Faze]

Had mine at 44 as well from MD, drove 1500 miles on them until I saw a post here that it's too much. Lowered it to 38 but don't like it that much. With 44 it felt like driving sporty SUV, 38 feels way to soft. But don't want to mess up the tires too fast

 

[eltaco]

Mine were also at 44 from the factory.

I lowered mine to 38, though I see them get up to 43-44 during driving on a hot day especially. Not sure if I should lower them further or not.

 

[Chieffreeze]

Mine were also at 44 from the factory.

I lowered mine to 38, though I see them get up to 43-44 during driving on a hot day especially. Not sure if I should lower them further or not.

Same for me

 

[Cautionary Tale]

Had mine at 44 as well from MD, drove 1500 miles on them until I saw a post here that it's too much. Lowered it to 38 but don't like it that much. With 44 it felt like driving sporty SUV, 38 feels way to soft. But don't want to mess up the tires too fast

Thats the fun and excitement of 5 wheel tire rotations. It'll help you squeeze out some more life while keeping your spare always functional. I'll be doing my tire rotation next week when I get back and I'll put a little thinking into how to do it easiest and post my walkthrough.

 

[RADA]

This is really good info - thank you (and ChatGPT) for putting this together.

I'll target 35/36 psi in mine

Yup...

35-36 psi was what I was calculating while reading through this.
BOY! Us RHO owners is SMART!


The truck currently indicates that all tires are at 38 psi, except for the right front, which is at 39 psi, despite my adjustments during the last two Costco Gas runs. That tire has always done its own thing (black sheep of the tire family). Waiting for it to color its hair purple, and get a BIG COW nose ring..

I'll bump them down to 35-36 on my next gas run.

 

[BilletRHO]

Thats the fun and excitement of 5 wheel tire rotations. It'll help you squeeze out some more life while keeping your spare always functional. I'll be doing my tire rotation next week when I get back and I'll put a little thinking into how to do it easiest and post my walkthrough.

Do you know if the spare has a TPMS or do you plan to have one installed?

 

[Cautionary Tale]

Do you know if the spare has a TPMS or do you plan to have one installed?

Haven't looked, as it's a full-size spare and vehicle is AWD, it has to be rotated into the mix to have any functionality. Would be shocking if they didn't include a TPMS to handle the task.

Yup...

35-36 psi was what I was calculating while reading through this.
BOY! Us RHO owners is SMART!


The truck currently indicates that all tires are at 38 psi, except for the right front, which is at 39 psi, despite my adjustments during the last two Costco Gas runs. That tire has always done its own thing (black sheep of the tire family). Waiting for it to color its hair purple, and get a BIG COW nose ring..

I'll bump them down to 35-36 on my next gas run.

Best to do it in morning before driving on them. If you do 35-36 on a gas run, you might end up 32-34 (depending on temperature and distance)

 

[gram10]

Do you know if the spare has a TPMS or do you plan to have one installed?

spare does not have tpms, found out the hard way trying to do a 5 tire rotation.
there's a sticker on the spare that says "spare"

 

[Cautionary Tale]

spare does not have tpms, found out the hard way trying to do a 5 tire rotation.
there's a sticker on the spare that says "spare"

WOW! My truck even came with an extra set of TPMS for a trailer. Odd the spare wouldn't have one.

I especially love that they felt need to put a sticker labeled "spare". I want to meet the guy that looks at the back of the truck and thinks "I wonder what the hell that round thing is under there"

 

[BilletRHO]

So it is possible to add a tpms and will the truck auto learn the new rotation? My Ford did

 

[Dcchris311]

I set my tp at 36psi cold, once i start driving and the tires warm up, it's at ~40psi