How much psi?

username17km · **Joined:** Sun Sep 18, 2011 9:55 pm **Posts:** 34

I have new 225/75R 16 Firestone destination m/t's and im wondering what is the best psi to go with? i have no added weight on my kj and do not want to wear out my tires. the max psi is 80 my mechanic filled them to 45, is that too much?

thank you

lfhoward · **Posted:** Sat Nov 10, 2012 4:23 pm

Hi there, I think 45 psi may be too much. If you have the stock tire size (which I think you do), then go with the psi on the sticker inside the drivers door jamb. I think it will say to inflate your tires to 34 psi. Too much pressure may slightly increase gas mileage, but you lose traction on the road during emergency maneuvers. It also wears the center of the tread faster, as your tires will not sit flat on the pavement.

KJ_WHEELER_2010 · **Posted:** Sun Nov 11, 2012 10:33 am

At our shop we go by the tab on the doorjamb for the PSI. If its like a F250 or a truck that will be hauling or pulling a load we then go by the PSI on the side of the tire. For a stock Libby I would deff go by what it says on the doorjamb.

KJ Willy · **Posted:** Sun Nov 11, 2012 10:42 am

If you want proper wear of the tires, go by the door jam sticker but also do the chalk test on the tires to make sure you are getting the proper footprint for tread wear.

ATXKJ · **Posted:** Sun Nov 11, 2012 9:07 pm

Door jam
with the caveat - LT tires take higher pressure than P or SL tires
http://nittotire.com/Content/pdf/Replacing%20Tires%20on%20Light%20Trucks%20-%20Technical%20Bulletin.pdf

SavageUrge · **Posted:** Mon Nov 12, 2012 3:17 am

I have to disagree with everyone here. Go by the the sidewall of the tire, NOT the door jam. The numbers on the door jam are for the OEM tires. So unless you replace the tires with the same ones that came on it, you go by the sidewall on the tires. Personally, I inflate my tires to just under the maximum inflation and always have nice smooth, even tire wear.

spitfire36o · **Posted:** Mon Nov 12, 2012 9:52 am

45 is too hard. The jeep is going to hop all over the place. I have the treadwright wardens (BF Goodrich all terrain tread copy). They are load rating E and I ride at 38 PSI.

tommudd · **Posted:** Mon Nov 12, 2012 10:38 am

Never do you run tires at or near the max inflation
Only time maybe if you have a ton truck and carrying near max loads, certainly not on a KJ/KK .
But even then you'd want to be careful due to when the tires heat up they maybe over the max PSI.
265-75-16s on mine at 34 lb with over 49,000 miles on them so must be wearing pretty good :ROTFL:

username17km · **Joined:** Sun Sep 18, 2011 9:55 pm **Posts:** 34

thank you for all the help ill just go with the door jam i guess, i kind of liked the ride at 45 but whatevers best for my renny lol

tjkj2002 · **Posted:** Mon Nov 12, 2012 1:06 pm

username17km wrote:

thank you for all the help ill just go with the door jam i guess, i kind of liked the ride at 45 but whatevers best for my renny lol

I'd try about 38-40psi,that was the best psi range when I ran 225/75R16 MT/R's.LT's in the D and E range will require a little more psi then P metric tires and even C range LT tires.

tjkj2002 · **Posted:** Mon Nov 12, 2012 1:07 pm

SavageUrge wrote:

I have to disagree with everyone here. Go by the the sidewall of the tire, NOT the door jam. The numbers on the door jam are for the OEM tires. So unless you replace the tires with the same ones that came on it, you go by the sidewall on the tires. Personally, I inflate my tires to just under the maximum inflation and always have nice smooth, even tire wear.

Sure you may get away with it running P metric tires but not running a D/E LT tire on a KJ.E range LT's max psi is 80 unlike 44psi for your P metric tires.

username17km · **Joined:** Sun Sep 18, 2011 9:55 pm **Posts:** 34

tjkj2002 wrote:

username17km wrote:

thank you for all the help ill just go with the door jam i guess, i kind of liked the ride at 45 but whatevers best for my renny lol

I'd try about 38-40psi,that was the best psi range when I ran 225/75R16 MT/R's.LT's in the D and E range will require a little more psi then P metric tires and even C range LT tires.

ill go with this, my tires are rated as E range and 33 just seems a bit low 38-40 psi seems best being roughly half or half the max psi. thank you

How much psi?

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