33" Cooper STT tire pressure
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JK Freak
Joined: Nov 2006
Posts: 805
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From: Albuquerque, NM
33" Cooper STT tire pressure
For those of you running these tires, what pressure are you using for the street?
Installer had them at 45 psi, seemed a little excessive...
Thanks,
glwood6
Installer had them at 45 psi, seemed a little excessive...
Thanks,
glwood6
JK Enthusiast
Joined: Jan 2007
Posts: 174
Likes: 0
From: Central FLORIDA
Nice JK by the way,
I saw pics of your JK posted in the Show and Tell Jeep Green post.
https://www.jk-forum.com/forums/show...?t=2060&page=3
Here is Mine,
I assume you are asking about on the road tire pressure? I have 33 x 12.5 "D" rated tires, sidewall says 50 psi, I did the chalk test, Started at 50 psi and am now running at 26 psi, they feel better and the chalk proves they are contacting the ground evenly across the tread.
Have you chalked them?
Again I must say that GatorGreen JK of your looks GREAT!
https://www.jk-forum.com/forums/show...?t=2060&page=3
Here is Mine,
I assume you are asking about on the road tire pressure? I have 33 x 12.5 "D" rated tires, sidewall says 50 psi, I did the chalk test, Started at 50 psi and am now running at 26 psi, they feel better and the chalk proves they are contacting the ground evenly across the tread.
Have you chalked them?
Again I must say that GatorGreen JK of your looks GREAT!
Last edited by GatorGreenJK; Jul 13, 2007 at 05:57 PM.
JK Jedi Master
Joined: Nov 2006
Posts: 15,170
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From: .
Here is a good description of the "chalk test"
there is not "simple" math as there are too many variables in tire/belts/whatever. Do a "chalk test"
1 piece of chalk, the kiddy sidewalk kind works well
a tire pressure gauge
a big parking lot with no cars and a nice strait run of say 500 feet
Drive around a bit to get the tires nice and warm and flexible.
get to one end of parking lot
aim vehicle across with the wheels strait
rub chalk across the entire tread of all 4 tires in a nice width as so you can find it.
drive forward, NO STEERING, for 500' or so.
stop
look at the chalk.
You will notice (almost 100% of the time the first time out) that the "center of the tread will have no chalk and the outers will.
deflate 5-10 psi
repeat until almost all the tread is wearing evenly.
My 35's are running 28psi all the way around and are quite happy
1 piece of chalk, the kiddy sidewalk kind works well
a tire pressure gauge
a big parking lot with no cars and a nice strait run of say 500 feet
Drive around a bit to get the tires nice and warm and flexible.
get to one end of parking lot
aim vehicle across with the wheels strait
rub chalk across the entire tread of all 4 tires in a nice width as so you can find it.
drive forward, NO STEERING, for 500' or so.
stop
look at the chalk.
You will notice (almost 100% of the time the first time out) that the "center of the tread will have no chalk and the outers will.
deflate 5-10 psi
repeat until almost all the tread is wearing evenly.
My 35's are running 28psi all the way around and are quite happy
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JK Newbie
Joined: Dec 2006
Posts: 20
Likes: 0
From: S.W. Virginia
On my unlimited Rubi, door sticker said 37 lbs for stock tires, after chalk test lowered to 26 lbs all was well. With my 35" Coopers, tire dealer put in 50 lbs, needless to say I was all over the road, after chalk, now running 24 lbs, all is well!!!