WHAT TIRE PRESSURES DO YOU RUN?

[hawaii]

35" TrXus MT on my XJ, I run 26lbs on the street, and often drop down to 8-10lbs off-road in the snow.

 

[Chuck59]

You are correct

Against the grain here, but I run 32psi street on the JK and 35psi on the XJ. 35was necessary on the XJ as it would get squirly on corners (freeway speeds) with the 315/75r16 MTRs(gen 1 not Kevlars) at 32psi, 35psi fixed that handling issue brought on by the tires. The previous set of BFGs had no issues. I have run less to get the jeep home after a trail run but for the most part that is the pressures I have run with good results. I typically get more mileage out of my tires than most without any weird tread wear such as cupping and I also run them down to almost nothing so I see long term results with even wear across the tread.

Potential issues I see with the chalk line method are overheating the sidewalls on freeway driving and tread cupping. I think it is possible to rely too much on the sidewall stiffness to support the vehicle with less air pressure than fully support the sidewall with the manufacturers recommended air pressure. 28psi is by no means low air pressure but having seen the difference from 32-35psi I am weary of running much less than the typical recommendation from the vehicle manufacturer. So many variables; actual vehicle weight, suspension ability to dampen the tires, tire rating, actual tire sidewall strength.. Maybe the chalk line is the best mothod for tuning the pressure?

Many of our tires are Light Truck & SUV tires. Off the road tire pressure can be lowered. But on the road, as a daily driver, if not aired up to a reasonable number, the sidewalls will constantly be flexed which creates heat and sidewall deterioration and poor (even dangerous) handling characteristics. This is particularly important at highway speeds. Also, higher air pressure will reduce rolling resistance and increase your mpg.

 

[quickfarms]

I have used the chalk method for 30 years on multiple vehicles with no bad results. This is over 500,000 miles at freeway speeds.

Rotate and rebalance your tires every 5000 miles and they will wear evenly even with the old ford suspension.

For the big trucks, class 8, we gave charts that show the pressure for a given weight. Loading does affect the manufactures recommended pressure. The number on the side wall is at the stated max load.

 

[highlandercj-7]

It goes by weight and tire contact for sure. The larger tires don't need as much pressure. I run 35" SSR Swampers on 15x10" Wheels, 22-26 on the street and 15 on the trail.

 

[JIMBO]

:sombrero: I run 30psi in my 33.6" Hankook Dynapros on highway-

I don't airdown off-road unless it's VERY soft sand or snow, but

My JKUR has advantages over most other 4x4s-

:costumed-smiley-007:wings: JIMBO

 

[bob91yj]

Usually around 30 PSI in my LJ with 315/75/16 BFG AT's. On the trail I start at 10-12psi and adjust from there, more for comfort than necessity.

On my rock Jeep with beadlocks and Interco TSL/SWX's I'll run 3-5psi in the rocks. They are bias ply's and stiff as all get out, damn near flat proof.

 

[BigRedXJ]

I run 24 psi on the street and 5-8 psi off road with a 35x12.5 Cooper STT on 15x8 bead lock rims. Jimbo, I can't imagine 30 psi working that well off road. Regardless of what advantages you have. As someone who's played around quite a bit with different tires sizes and different pressures I know that 30 psi won't serve too well in hard terrain, even with the dual lockers of a Rubi. I'm curious to know what advantages you have that make it ok to run 30 psi off road and what kind of terrain you're usually on.