I have a 2000 TJ and I bought a set of BFG Mud Terrains and rims off of a 2016 Willys. They are 255/75/17. What is the best tire pressure for street driving?
Tire pressure
- Thread starter OJeepO
- Start date
That's roughly a 32" tire so probably 29-30 psi is about right. Never go by the psi pressure molded onto a tire's sidewall, that only indicates the tire's max safe air pressure. The correct tire pressure depends on the weight of the vehicle it is supporting, the tire size, and the tire's Load Range as in C, D, or E. A Load Range C tire is appropriate for a Wrangler.
Erik V
TJ Enthusiast
I’m running BFG 33X10.5X15 on my 06 TJ.
What’s a good pressure?
I just bought the rim & tire package about 3 months ago a I believe/ feel there to the max tire pressure. ( I never checked, my bad).
What’s a good pressure?
I just bought the rim & tire package about 3 months ago a I believe/ feel there to the max tire pressure. ( I never checked, my bad).
27 psi around town when lightly loaded, 29 psi when fully loaded with people or gear on the highway. For 33x12.50R15 tires it's 26 and 28 psi but the 10.5" wide version needs just a touch more air.
Erik V
TJ Enthusiast
Thanks Jerry27 psi around town when lightly loaded, 29 psi when fully loaded with people or gear on the highway. For 33x12.50R15 tires it's 26 and 28 psi but the 10.5" wide version needs just a touch more air.
I have Cooper A\T 33x12.5 R15's on my LJ and am struggling with the pressure and adjustable shock setting (rancho 9000) to get a comfortable ride, am trying 24 lbs. to see if that helps. Was at 26
OP
What setting are your shocks at? And are they the 5-way adjustable RS9000 or 9-way RS9000XL? 24 psi is a bit light for 33's.
Shocks are 9-way, set at 4 on the front and 3 on the rear.
Also thank you for the referral to John at All 4 Wheel, ended up having him do the gearing, and lift install.
Also thank you for the referral to John at All 4 Wheel, ended up having him do the gearing, and lift install.
Glad you had a good experience with John, he's one of the very best in SOCAL. Are your tires Load Range C, D, or E?
That you're having a stiff ride with Load Range C tires with 26 psi in them and your shocks set at the settings they are is surprising. I would not go lower on the tire pressure which is as low as I'd run with those tires. Instead I would try going down a setting or two on your shocks.
Went to a lower setting and big improvement, I actually had them set higher than I thought so am now at 3 at front and 2 on the rear. Am thinking it would be wise to get an extra set of adjustment knobs. Going on an easy trail this weekend but Murphy might ride along!
Thanks for the input.
Thanks for the input.
This "pigheaded Dutch selfdeclared tirepressure-specialist " registed to this forum to give you and answer.
Story began when I got hold of the official used european formula for that and went running with it.
Dont have a Jeep so wont introduce me in a seperate topic, if needed write it and I will.
When I am right the Jeep is a relatively light vehicle with oversised tires , even if they would be P-tires.
This yustifies a low pressure. Even lower then the 26 psi mentioned here, wich is the lowest they go in America.
In the copy I got from standards manual 2007 of ETRTO , it is adviced not to go lower then 150kPa/22psi.
But if you would calculate it with the to natures law ideal formula , you could even go as low as zero pressure , if the load is low enaugh ( estimated 5% of maximum load of tire).
Todays rimms mostly have 2 humps ( 2 times PANG when mounting tire to rimm) wich keep the tire on the rimm.
What I need to calculate it for you is this.
From Jeep : weights on seperate wheels best, second best axles , if not we use the GAWR's ( gross axle weight ratings, then you have advice for fully loaded, normal use us lower).
Also give GVWR ( V for Vehicle) and empty weight and the way you load it for the situation..
And maximum speed you use and wont go over for even a minute.
Then from tires next:
1 Maximum load or loadindex
2 Kind of tire (loadrange here mentioned C-load or P tire in Standard load ( SL) or XL/Extraload/Reinforced).
This to determine the pressure for wich the maximum load is calculated up to 160km/99m/h( or if speedcode lower then Q max speed).
3 speedcode.
Try to deterine this all as acurate as possible and give it here, then I will give an advice with reserve that has still acceptable comfort and gripp, and wont overheat your tires for onroad driving.
For offroad 2 lower advices are given. for on track mostly about 80% of the pressure for 65km/30m/h, and for in mud/sand mostly about 50% of onroad pressure for 20km/12.5m/h, in pressure lists from tiremaker.
Story began when I got hold of the official used european formula for that and went running with it.
Dont have a Jeep so wont introduce me in a seperate topic, if needed write it and I will.
When I am right the Jeep is a relatively light vehicle with oversised tires , even if they would be P-tires.
This yustifies a low pressure. Even lower then the 26 psi mentioned here, wich is the lowest they go in America.
In the copy I got from standards manual 2007 of ETRTO , it is adviced not to go lower then 150kPa/22psi.
But if you would calculate it with the to natures law ideal formula , you could even go as low as zero pressure , if the load is low enaugh ( estimated 5% of maximum load of tire).
Todays rimms mostly have 2 humps ( 2 times PANG when mounting tire to rimm) wich keep the tire on the rimm.
What I need to calculate it for you is this.
From Jeep : weights on seperate wheels best, second best axles , if not we use the GAWR's ( gross axle weight ratings, then you have advice for fully loaded, normal use us lower).
Also give GVWR ( V for Vehicle) and empty weight and the way you load it for the situation..
And maximum speed you use and wont go over for even a minute.
Then from tires next:
1 Maximum load or loadindex
2 Kind of tire (loadrange here mentioned C-load or P tire in Standard load ( SL) or XL/Extraload/Reinforced).
This to determine the pressure for wich the maximum load is calculated up to 160km/99m/h( or if speedcode lower then Q max speed).
3 speedcode.
Try to deterine this all as acurate as possible and give it here, then I will give an advice with reserve that has still acceptable comfort and gripp, and wont overheat your tires for onroad driving.
For offroad 2 lower advices are given. for on track mostly about 80% of the pressure for 65km/30m/h, and for in mud/sand mostly about 50% of onroad pressure for 20km/12.5m/h, in pressure lists from tiremaker.
Not always and not usually. Very few people know how to properly interpret the chalk test's results, most end up with often grossly under inflated tires trying to get the chalk off the entire width of the tread. Few tires are designed for 100% of the tread to touch the road surface except perhaps during hard cornering or while rock crawling..
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Oh thank goodness! Jerry I finally found something that we don't agree on. I always look to you for advice and usually just find it in your post or the how to section and from Chris. I'm going to celebrate and keep this one thing for me. I sure do appreciate you but boy howdy I think I'm right on this one. Given of course that you find out how much of your tread should be touching the ground on a particular tire. I spent the weekend at an off-road event and talked to the BFG guys about my tires and they walked me through it quite simply.
Thank you sir,
Roy