Tire air pressure

[Proptrash]

Dealer set 37/38 on my XR, became 39/40 these couple warmer days. I can feel a bit bumpy ride on poorly paved roads. Will down to 35 today to see if any difference. And may go a bit lower as long as the TPMS alert doesn’t come up to northern me.

Dealer had had mine 40+. Drove it home and lowered to 33/34. Much better!

 

[hardhat]

I've been running 28 psi on the stock KO2s on my XR. No discernible impact on fuel economy. Rides and handles better at this pressure. This is what AEV recommended for the JK. If I ever get around to it, I'll do a chalk test, but even at 28 psi on my JK, the middle part of the tire wore more than the outside part of the tire. I'll see how mine are wearing over time and adjust pressure based on that, but at this point can't bring myself to go lower than 28..........

To me, the perfect pressure would be where the middle and edge of the tire would wear at the same rate. Would be cool to have one of those pressure sensitive pads like you stand on to show pressure distribution of your feet. That way you could get the contact pressure on the edge of the tire to be same as in the middle.

But crap, I'm too busy to do a chalk test much less investigate a contact patch analysis machine...

 

[Keithbickford]

Go by the tire rating (stamped on sidewall).
door only reflects OEM. Every manufacturer and every model varies. They are all designed for a specific PSI for road driving, factoring in safety, wear, mileage and handling based on load

Honestly worse advice ever. Sorry, but when it comes to safety, I have to be honest. The pressure stamped on the side wall is maximum pressure at the maximum weight rating, and is the absolute maximum tire pressure for that tire on any vehicle. Does your Jeep weigh 10,000 pounds?
It has nothing to do with the recommended tire pressure on a Jeep Wrangler.
You’ll hear a lot of advice and ideas on how much tire pressure to run. And honestly, there’s no perfect solution.
Some may say to do the chalk test. It’s actually easier for us on our jeep with very little camber. Tried to slide a piece of paper under the tire. If you can slide the paper under the tire, it may be overinflated. Deflate until you can no longer slide the paper into the tire.
Using this method will maximize the contact patch. But it will cause someway in turns. So I would not go any lower than that on the road.
When you load up your jeep, you’ll have to add some more in the back. Likely not in the front.
When my 2024 Jeep Wrangler 392 was completely stock, I was running 28 in the front and 24 in the back to get similar contact patch on all four tires. Now that I have a lot of gear in the back, it’s actually 28 front and 34 rear. Big difference.
37 psi is way too much for our jeeps. That helped Jeep get some fuel economy numbers that they were looking for, but your Jeep will ride like . You may slide to a stop, especially when it’s wet. Your wheels will bounce uncontrollably over bumps. If you hit a bump at highway speed, it will rattle your steering wheel and your teeth.

 

[Earl 392]

I've been running 28 psi on the stock KO2s on my XR. No discernible impact on fuel economy. Rides and handles better at this pressure. This is what AEV recommended for the JK. If I ever get around to it, I'll do a chalk test, but even at 28 psi on my JK, the middle part of the tire wore more than the outside part of the tire. I'll see how mine are wearing over time and adjust pressure based on that, but at this point can't bring myself to go lower than 28..........

To me, the perfect pressure would be where the middle and edge of the tire would wear at the same rate. Would be cool to have one of those pressure sensitive pads like you stand on to show pressure distribution of your feet. That way you could get the contact pressure on the edge of the tire to be same as in the middle.

But crap, I'm too busy to do a chalk test much less investigate a contact patch analysis machine...

28-30 cold is a good psi the 37 is way too much

 

[Earl 392]

Yep, larger tire volume = less air pressure required. There are calculators on line. In my LJR I run 25 psi in load range C 35's. I shocked the new jeeps have recommendations in the high 30's. I was riding with a buddy in his 2 door JK and was getting my teeth rattled out on easy trails. He said his door sticker says 38 so thats what he runs.

Off road 38 is 17 psi for c rated 33 or 35 is good or 12-15 if it’s a nasty trail ( c rated). 10-12 for d or E rating 25 psi on road for D or E is also a sweet spot

 

[3TV]

The weight of the vehicle obviously has a lot to do with how much air pressure you need in your tires. I weighed my 392 after adding skid plates, rock sliders, bumpers, winch, tools, recovery gear and survival gear. It weighs 6550 lbs on the local CAT scale, which is well above the 5300 lb advertised weight from Jeep.

I set my on-road tire pressure to achieve the best contact patch with the road, so as to avoid only running on the center of the tread. It turns out that 28 psi is the perfect on road air pressure for my 40" load range C Toyo MTs. Off road I typically run 12 psi, +/- a few PSI depending on conditions.

Reset the low-pressure warning threshold with a Tazr, or similar device. I set mine at 25 psi, so I have no warning lights while on road.

 

[Earl 392]

The weight of the vehicle obviously has a lot to do with how much air pressure you need in your tires. I weighed my 392 after adding skid plates, rock sliders, bumpers, winch, tools, recovery gear and survival gear. It weighs 6550 lbs on the local CAT scale, which is well above the 5300 lb advertised weight from Jeep.

I set my on-road tire pressure to achieve the best contact patch with the road, so as to avoid only running on the center of the tread. It turns out that 28 psi is the perfect on road air pressure for my 40" load range C Toyo MTs. Off road I typically run 12 psi, +/- a few PSI depending on conditions.

Reset the low-pressure warning threshold with a Tazr, or similar device. I set mine at 25 psi, so I have no warning lights while on road.

 

[Keithbickford]

28-30 cold is a good psi the 37 is way too much

As an alternative to chalk, I have a very thin insurance card that I slip under the edge of the tire. It slips in about 1/4” at 28 psi.

 

[Dubai_Bulldog392]

Curious what everyone is running for tire pressure while on-road?? I have always followed the door stickers on all my vehicles (including previous Jeeps), but I've seen a few posts about people running 30-32psi with their 392's.

I am running Yokahama 37 MT Geo's on 17 inch Bajabuilt Rims: On the road 36 on the sand 6psi