Rubicon Steering & Tire Pressure?

JIMBOX

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Everybodys pissing on my cornflakes--

I don't get the "LOW PRESSURE WARNING ALARM", BECAUSE THE ECU has put the TPMS SYSTEM on standby (owners manual), because I don't have any TPMS xmitters in my wheels and the ECU corrects for that after 20 minutes at 15 mph --ONE TIME-

My dash display fpr tire pressure shows the body outline with red lines, where the pressure WAS and it says "TIRE PRESSURE NOT AVAILABLE"

I've said that I have a 2dr and the 4dr NON-RUBICON/RUBICON-WILL BEHAVE DIFFERENT AND I DON'T DRIVE MY 2DR ON THE FREEWAY--I DON'T WORK/I DON'T COMMUTE-ETC--

Any time I have to got to Ca. I take my RAM, my 2dr RUBY is just for fun, now probably before XMAS I'll hit the freeway to run the SIERRAS before Winter, but I have no worries about steering/power/braking and I don't care about tire mileage, THE REST OF THE TIMEIN IN THE NorNv DESERT !

W.E.

JIMBO





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jeremyjeep

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Steering problems go way beyond tire pressure issues:

1. Steering survey results: https://docs.google.com/forms/d/e/1...xM0ZQzjhMVaXo8TICWUZN3xrsSpGo3g/viewanalytics
2. To add your data into the survey: https://goo.gl/forms/uWOyTgyqG6AnNdEY2
3. Spread sheet version: https://docs.google.com/spreadsheet...AMpdgKt1oA5sT_aXI-hoYMCg4/edit#gid=1437013635
4. I found this steering survey info here: https://www.jlwranglerforums.com/forum/threads/wrangler-steering-issues-survey.12343/
5. If you type in Google 2018 Jeep Wrangler JL, before you finish typing, Google adds steering issues to the end of the keyword phrase as the first suggestion. Obviously there are serious steering problems @JeepCares
6. Check out the recent spike in Google searches on Jeep Wrangler steering related keyword phrases below. Date range is 1/1/2004 to 8/27/18. Source: https://trends.google.com/trends/explore?date=2004-01-01 2018-08-27&geo=US&q=Jeep Wrangler steering. According to the Google keyword tool, there were 6,345 searches for Jeep Wrangler steering related keyword phrases in the last 30 days.

Interesting - Law firms are now creating dedicated web pages for Jeep Wrangler JL steering problem related lawsuits: https://www.lemberglaw.com/2018-jeep-wrangler-problems-complaints-lemon/

jeepsteeringsurvey.jpg
 
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xeon

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I agree. While it may not be the cause of all the tracking/steering problems, the high psi causes the JL/JLUs and previous gen Wranglers to handle poorly(more than they do normally). The higher PSIs(especially the 40+ that dealers are leaving from the factory) while doesn't make them "track" crooked, causes the tires to follow every road imperfection.

I am on my fifth Wrangler from four different generations (TJ,XJ,JKU,JLU) and have always run my tires, what the manufacturer would consider low. I ran my JKUS(traded in w/42,000 miles and the tires look brand new(except for the sidewalls (rock crawling) & got 16-18 MPG)), and now my JLUR @ 32 PSI.

I am a first time JEEP owner. I have driven JKs, JLU Sports, JLUR. etc. All of which have slightly different characteristics in steering. However after reading this post, i lowered my psi from 36 to 32. Wow...what a difference. I thought for sure fuel economy would be effected but after 500 miles...there is no noticeable difference at all. I don't feel like I am driving under the influence at freeway speeds now. Thanks for the tip.
 

Udi

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I realize this thread is a year old but I didn't find a current one for this subject. I got my new 2 door 2020 Rubicon last Saturday and have been driving it a lot both on/off road since. What I've found with regard to the factory specified tire pressure (37 psi) is that the steering is too sensitive and the handling is outright difficult at highway speeds (75). 2-door Rubys are more sensitive than 4-doors but I thought that highway handling was just not acceptable.

Off road, I've dropped the pressure to 20-23, depending on the terrain, which was perfect.

When I aired the tires back up I set the tire pressure to 31 psi, and the drive and handling got so much better. At highway speeds the tire pressure rose to 33. Today after reading this thread I got concerned that my tire pressure may be too low for the road so I decided to do a chalk test. With the tires at 30/31 psi I ran the chalk test twice and this is what I got on both front and rear tires:

20190904_172536.jpg


This is the first time I'm doing a chalk test but having chalk left untouched on almost an inch on both sides of the tires tells me that the tires are definitely not under-pressurized and possibly still a little over pressurized, right? I mean, the center of the tire will wear out before the sides will. So, I don't understand why is the factory specifying a tire pressure that is way too high for this tire/load combination? Is there any downside to driving with 30/31 psi?

By the way, my gas mileage average for the entire trip up to the mountains, some serious off roading, and back home was 23 MPG. Not too shabby! So I don't see a downside there...
 

HealthRebel

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Aired down to 37 psi over lunch and instantly noticed an improvement. Thanks everyone for your help!
Same for me. 2020 JLRU was at 42 psi when I picked it up. Wondering on the highway. I dropped them to 37 psi and roughly 98% improvement. I have been playing with the air pressure from there. So far, my sweat spot I like is 34 psi. Now... 100% improvement. NO steering issues. Perfect!!!
 

Joker4L

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My 18 Sahara JLU on 18”s was running 36lbs and wandered a lot. Was miserable actually. I went out and got me 17” stock Rubicon wheels with the KO2 tires and I aired them down in the early AM to 31PSI and it made a huge difference. There is still about 2 in play in the steering whee but the car tracks much smoother. Car is also so much smoother on the road and the gas mileage is the same. No difference :)
 
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Uhdinator

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I realize this thread is a year old but I didn't find a current one for this subject. I got my new 2 door 2020 Rubicon last Saturday and have been driving it a lot both on/off road since. What I've found with regard to the factory specified tire pressure (37 psi) is that the steering is too sensitive and the handling is outright difficult at highway speeds (75). 2-door Rubys are more sensitive than 4-doors but I thought that highway handling was just not acceptable.

Off road, I've dropped the pressure to 20-23, depending on the terrain, which was perfect.

When I aired the tires back up I set the tire pressure to 31 psi, and the drive and handling got so much better. At highway speeds the tire pressure rose to 33. Today after reading this thread I got concerned that my tire pressure may be too low for the road so I decided to do a chalk test. With the tires at 30/31 psi I ran the chalk test twice and this is what I got on both front and rear tires:

20190904_172536.jpg


This is the first time I'm doing a chalk test but having chalk left untouched on almost an inch on both sides of the tires tells me that the tires are definitely not under-pressurized and possibly still a little over pressurized, right? I mean, the center of the tire will wear out before the sides will. So, I don't understand why is the factory specifying a tire pressure that is way too high for this tire/load combination? Is there any downside to driving with 30/31 psi?

By the way, my gas mileage average for the entire trip up to the mountains, some serious off roading, and back home was 23 MPG. Not too shabby! So I don't see a downside there...
37 psi...........likely derived from vehicle weight plus capacity of 4 persons and a full tank of fuel.

My 2dr specs from door jam:
245/70 tire 36 psi F and R
max capacity 700 lbs 4 passengers
(vehicle is not the same weight F/R they just divide total weight by 4 to get a general psi number)

I have 305/65 tires rated for an 8-10" wide wheel, my wheels are 8.5":
8" rim will require less psi than a 10" rim to keep the contact patch/tread flat in the road.
With a wider tire/bigger contact patch, weight is distributed over a larger area. inflating to spec will wear the tire out in the middle. Stock C rated vs. My E rated MT tires are not as stiff less side wall ply's hence higher psi in the stock tires so they are not to squishy.

To verify your chalk test also watch your psi change when tires get warmed up. After your jeep sits all night, check and set your tire Psi to a couple psi below where you want it. Go for a drive (highway speeds) and check pressure after 10-15 minutes. Your psi shouldn't increase more than about 10% or 3-4 psi. If your psi goes up more, you're under inflated and increased heat causes increased psi.

My advice is to chalk both a F and R tire and adjust as needed. Here is a pic of my Challenger with the tires at spec/same psi in all 4 tires. The back tires are wider than the front. You can tell the rear tire is not fully on the ground compared to the front. I ended up increasing the front psi a few psi and decreasing the rear a few. The back tire is on the left (less weight on it, and bigger contact patch. (notice the contact patch goes beyond the siping lines on the front tire and much less on the rear tire.

The spec'd psi is also a balance of MPG vs. tire life. I prefer to favor better tire life and better ride over MPG.
You might find you want a few less psi in the rear than in front.
Salty tire pressure guage.png
 

metallicpea

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To add my data point, I have a 2 door with a build date of 4/5/2019.

It arrived straight from the plant with 42 psi in the tires. It did not have a unacceptable dead zone in the center of the steering, but the steering was was to frenetic / twitchy on the highway. It was quite difficult to keep it headed in a straight line.

After finding this thread or a similar one, I lowered to 32 psi all around and it is much improved. I would say acceptable, although it still does not track as well as my LJ on the highway - probably just a matter of the shorter wheel base.
 
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mtnbikeracer76

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Don't forget another reason for higher tire psi recommended by Jeep.

Firestone Tire Recall from the early 2000's.
 

Udi

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Well, I'm glad that most everyone agrees that running the Ruby tires in the low 30's is fine. Now if I could only disable the useless low-pressure warning alarm on the dash... :(

Edit - just read in another thread that there is a device called Tazer that can be used to reprogram the TPMS settings. But it's expensive... Anybody cares to loan/rent their Tazer? Is there a place that would do that for me?
 
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Joker4L

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Well, I'm glad that most everyone agrees that running the Ruby tires in the low 30's is fine. Now if I could only disable the useless low-pressure warning alarm on the dash... :(

Edit - just read in another thread that there is a device called Tazer that can be used to reprogram the TPMS settings. But it's expensive... Anybody cares to loan/rent their Tazer? Is there a place that would do that for me?
You can only use the device on one vehicle at a time as it binds to the vehicles vin #. You will have to buy your own.

You can also buy a Flashcal which also does almost everything the tazer does for much cheaper. I snagged an open box deal on amazon for $175. It works amazing
 

RagTopDeluxe

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To add my data point, I have a 2 door with a build date of 4/5/2019.

It arrived straight from the plant with 42 psi in the tires. It did not have a unacceptable dead zone in the center of the steering, but the steering was was to frenetic / twitchy on the highway. It was quite difficult to keep it headed in a straight line.

After finding this thread or a similar one, I lowered to 32 psi all around and it is much improved. I would say acceptable, although it still does not track as well as my LJ on the highway - probably just a matter of the shorter wheel base.
If you haven’t read the steering threads, a couple things to check:
- check the alignment for toe and caster. I had to put longer LCAs to get the caster to 6 (I have a non-lifted JLR) and that helped a lot.
- check the torque on the components (my sway link bolts were loose and that also made a big difference in the looseness)
 

Saltysnook

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I realize this thread is a year old but I didn't find a current one for this subject. I got my new 2 door 2020 Rubicon last Saturday and have been driving it a lot both on/off road since. What I've found with regard to the factory specified tire pressure (37 psi) is that the steering is too sensitive and the handling is outright difficult at highway speeds (75). 2-door Rubys are more sensitive than 4-doors but I thought that highway handling was just not acceptable.

Off road, I've dropped the pressure to 20-23, depending on the terrain, which was perfect.

When I aired the tires back up I set the tire pressure to 31 psi, and the drive and handling got so much better. At highway speeds the tire pressure rose to 33. Today after reading this thread I got concerned that my tire pressure may be too low for the road so I decided to do a chalk test. With the tires at 30/31 psi I ran the chalk test twice and this is what I got on both front and rear tires:

20190904_172536.jpg


This is the first time I'm doing a chalk test but having chalk left untouched on almost an inch on both sides of the tires tells me that the tires are definitely not under-pressurized and possibly still a little over pressurized, right? I mean, the center of the tire will wear out before the sides will. So, I don't understand why is the factory specifying a tire pressure that is way too high for this tire/load combination? Is there any downside to driving with 30/31 psi?

By the way, my gas mileage average for the entire trip up to the mountains, some serious off roading, and back home was 23 MPG. Not too shabby! So I don't see a downside there...
Can you describe how you performed your chalk test to get the results in the photo?
 

Benagi

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I'll just have to assume that you feel that I'm a drunkard/drugeeD, or live in a non-real world--

My post #4 is exactly the REAL DRIVING SITUATION and if you doubt my word, then I suggest you avoid any of my posts, because after driving off-road for over 64 years I have a VAGUE idea of solid axle tire tread and air pressure steering parameters--

If you're not happy with my opinion/ideas/remedies--complain to a MODERATOR and if you're right--BY BY !

W.E.

JIMBO
Wow, Jimbo, how old are you? I’ve been 4 wheeling since I was 18 and now have 50 years experience. Congrats on 64 years on off road and still going.
 

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