Tire Pressure / Stock Wheels & Tires

MerlinsGarage

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Dealer prepped the 392 with 44 psi in all 4. What a mess, Jeep was all over the place. Now running the posted tire pressure, 37 and behaves much better. Anyone have 35 or less (normal driving and load) for long(ish) term test? Curious to see if tire wear is an issue with this reduced pressure. I would guess it would Improve the ride.
Thanks,
Bret.
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Rhinebeck01

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You'll do far far better running at 32# in the Summer in PA and 34# in the Winter. 37# is way to much, especially in the Summer and well, even in the Winter...

Reason for the higher in the Winter is because when temps fall at night, etc., psi will drop below 32# and you will get an EVIC light warning.

DO check/change psi in the early morning before vehicle use and or Sun hitting tires... Use a decent tire gauge. Do not rely/trust to much, the onboard psi reading.

With psi as I mention steering will better as well as ride in general.

Research "Chalk Test" if you want to really get into the psi and your JL thing...

Also, remember your steering column is adjustable...

Adjust the steering column, so that you are not reaching for the steering wheel.

You want a bend in your arm. IF, you have to reach, your arms get tired easier/ faster and you will be causing the JL to wander thanks to those stretched out fatigued arms..

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BRuby

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Dealer prepped the 392 with 44 psi in all 4. What a mess, Jeep was all over the place. Now running the posted tire pressure, 37 and behaves much better. Anyone have 35 or less (normal driving and load) for long(ish) term test? Curious to see if tire wear is an issue with this reduced pressure. I would guess it would Improve the ride.
Thanks,
Bret.
We ran at the posted 37 and def had uneven tire wear. Was thinking sticker and all - manufacture would know best. Not even close. Then dropped to 32 with the spare on the first 5 tire rotation and tread wear was perfectly even at 1/32 across the tread. So def tread wear was an issue. Go 32 with stock KO2s and ride is lux. Steers straight all is good. Better traction in rain and snow as well. Always check and record tread depth at each rotation to confirm your wear pattern.

FSRs drop to 20 and blast float over deep ruts and potholes like a magic carpet. Ride is fantastic. Rubicon is unbelievable for that with C rated with stock suspension and shocks.
 

Rhinebeck01

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IF, if you run at 37# psi in the Summer, as soon as the Sun rises, outside temps increase.... ....compounded by your driving the vehicle on a very hot asphalt highway and those tires you inflated to 37# on now at 50# +- .

With tires at such high psi and your driving, the ride will be rough, handling will be impacted very negatively (wandering) and of course tire wear is increased..

With that said, in the hot Summer months, keep psi lower as you know what I mentioned will come into play....... Another words in the Summer your 32# psi inflated will end up being pretty much the 37# recommended on the door placard thanks to heat..

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Aonar

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T2.jpg
T3.jpg
T1.jpg

T5.jpg

Running 31-32 here in the summer. Notice in the last pic you can barely see the chalk on the outer edge. I repeated this test 2X. Once on a back, blacktop road and once on the concrete you see in this pic. Got almost identical results so I think/hope I did the testing correctly. Did these tests after our run out to CO (see other thread) to wheel and back. Stock JLURD, AT stock tires, empty of all camping gear for the tests, 3/4 seat delete, half doors...as seen in pic. When we get the deep snows/drifts I will air down just a little more...personal preference. I also ROTATE tires on a very regular basis, 3-4K miles and 5 tire rotation.
 

Rhinebeck01

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Running 31-32 here in the summer. Notice in the last pic you can barely see the chalk on the outer edge. I repeated this test 2X. Once on a back, blacktop road and once on the concrete you see in this pic. Got almost identical results so I think/hope I did the testing correctly. Did these tests after our run out to CO (see other thread) to wheel and back. Stock JLURD, AT stock tires, empty of all camping gear for the tests, 3/4 seat delete, half doors...as seen in pic. When we get the deep snows/drifts I will air down just a little more...personal preference. I also ROTATE tires on a very regular basis, 3-4K miles and 5 tire rotation.
@Aonar

Yup..... I, others see/saw same same with Chalk Testing..

In the Winter though if you run with 32# or less or a little above even, you will, on frigid mornings, etc., you will be faced with an Evic warning light. Light won't clear unless you reinflate to door placard psi and drive around abit..

With that said, for guys that want to run near or lower the 32# tires pressures in locales that get very cold temps, you will want to use say a Tazer JL Lite or Mini / JSCAN to change psi thresholds...Unless you don't mind seeing an Evic light.... And no, I do not say/suggest that a guy turn off TPMS for this Winter morning thing lets call it.

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Aonar

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@Aonar

Yup..... I, others see/saw same same with Chalk Testing..

In the Winter though if you run with 32# or less or a little above even, you will, on frigid mornings, etc., you will be faced with an Evic warning light. Light won't clear unless you reinflate to door placard psi and drive around abit..

With that said, for guys that want to run near or lower the 32# tires pressures in locales that get very cold temps, you will want to use say a Tazer JL Lite or Mini / JSCAN to change psi thresholds...Unless you don't mind seeing an Evic light.... And no, I do not say/suggest that a guy turn off TPMS for this Winter morning thing lets call it.

.
My light is constantly on now...no biggie for me. I check tires often. Have a tazer for the JK but not getting for this one yet until I eventually go up to 35's.
 
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MerlinsGarage

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Much appreciated guys! I knew I was asking the right group of folks.
I'm in eastern PA and temps in the 80s approaching 90. I'll move TP to 32 for the summer and bump it up to 34ish come fall. I use a calibrated analogue Intercomp gauge.
Thanks for the help.
Best regards,
Bret.
 

Rhinebeck01

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Much appreciated guys! I knew I was asking the right group of folks.
I'm in eastern PA and temps in the 80s approaching 90. I'll move TP to 32 for the summer and bump it up to 34ish come fall. I use a calibrated analogue Intercomp gauge.
Thanks for the help.
Best regards,
Bret.
@MerlinsGarage

Remember to only change psi in the early morning before you drive the JL... when tires are cold...
 

Rob97RR

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@MerlinsGarage

Remember to only change psi in the early morning before you drive the JL... when tires are cold...
Hey, dumb question, but what is an Evic light? Is that just for low tire pressure? It's not the same thing as a check engine light, right?
 

Rhinebeck01

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Hey, dumb question, but what is an Evic light? Is that just for low tire pressure? It's not the same thing as a check engine light, right?
@Rob97RR

There is no such thing as a "dumb question" ..... What would be dumb is if you did not ask a ?.
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Anyway, EVIC stands for: Electronic Vehicle Information Center (EVIC) Displays

Read here for generic EVIC display messages:
Note: the messages listed at this URL will not be exactly what you would see offered on a JL/JLU/JT..
http://www.jeeclub.com/reco-2029.html
 

Rob97RR

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@Rob97RR

There is no such thing as a "dumb question" ..... What would be dumb is if you did not ask a ?.
-------------------------------------------------------------------------------------
Anyway, EVIC stands for: Electronic Vehicle Information Center (EVIC) Displays

Read here for generic EVIC display messages:
Note: the messages listed at this URL will not be exactly what you would see offered on a JL/JLU/JT..
http://www.jeeclub.com/reco-2029.html
Thanks for the gracious reply, and thanks for the link!
 

Aonar

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Update on tire wear in post #21 here. Here is the snippet related to this thread:
FYI - this was over a distance of 3389 - 2545 of which was during the CO trip. Also posting this info to help validate that running my tires at MY "chalk test" pressure has done no harm whatsoever to over or under wear across the surface of the tread. At least, as per the mechanic.
 
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