Highway Driving

BillG

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Took delivery of our Rubi and dealer had 44psi in tires, not sure why they disregard door sticker.

Anyhow, settled in at 34/35psi and it’s perfect now.
I think maybe the factory does it to make sure the bead is truly seated, and the dealer doesn’t mess with it unless TPMS says it’s low.





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TIDALWAVE

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Boyle's Law: A lot of people seem to have not taken notes in their chemistry/physics classes. Yes, nitrogen is an 'inert' gas...but it expands/contracts with temperature changes just like other gases. Other than making some money for the dealership...nitrogen does not move through rubber as easily as oxygen, so tires do not deflate as fast as when filled with 'air'. One important factor for nitrogen-filled tires...is that the gas has had water moisture removed (the gas is 'dry'). It is water moisture in air-filled tires that expands and contracts more readily than dry air.
Instead of wasting money on using 'pure nitrogen'...use compressed air that has had water vapor removed!
 

Mowery

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I just picked up a fully loaded Rubicon JLU. I took it on my first highway/Interstate short trip. The Jeep wanders a lot in the lane and the steering is vague and a little abrupt when correcting with lots of roll. I don't remember my older Jeeps driving this way.

So do I have an alignment / toe in issue or is this normal for these now?

I had the same problem, adjusted toe, air pressure, added steering stabilizer. The fix was adjustable control arms and set the caster at 6.4 degrees (about a degree more than max spec). This could wear front u-joint prematurely, but at least I do not appear drunk while driving on the highway.

I would be interested to hear what other peoples' caster is set at and how the Jeep drives.
 

Drummer_G

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I just picked up a fully loaded Rubicon JLU. I took it on my first highway/Interstate short trip. The Jeep wanders a lot in the lane and the steering is vague and a little abrupt when correcting with lots of roll. I don't remember my older Jeeps driving this way.

So do I have an alignment / toe in issue or is this normal for these now?
This was the very first issue I noticed since switching from a 2015 Ram 1500. I didn’t notice it a lot until I got up over 65 mph. I actually don’t like driving this jeep much faster than 75. But when I think about it, with all that beefy suspension, it’s bound to drive a little differently. Not to mention that this vehicle is not made for speed.
 

Drummer_G

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You're noticing what so many others are. The JL drives like s****.

It has NOTHING to do with tires. So don't waste your time there.

Just yesterday, FCA released a TSB on this issue which may be the fix we've all been waiting for. It involves reprogramming the software to change the electric motor assist ratio. Check with your dealership to see if they can do this update for you and it may really help!

Mine PCM was flashed about two weeks ago and my Jeep drives considerably better now.
I’m going to have to try and this thanks!
 

JIMBOX

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NEWS FLASH--Tire pressure can make all the difference in the world t, I would say the majority of the off line JLs--

Every time a new owner takes the JL in for alignment/ECM check the dealer can bill Chrysler/FCA for at least $100 bucks-

When I drove my Ruby home from the dealer on SAT, it was all over the road---when I got to my garage I checked the tires air pressure--all were at least 49psi------

I set them to 30 psi and now she drives--close to perfect, almost no steering wheel correction all the way up to 70 mph--

I have a theory, but maybe later I'll postit-

W.E.

JIMBO
 
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I've had other cars that I know were filled with nitrogen and had reliable pressure sensors on the tires. I never saw them change with temperature.

I don't know if the Jeep came with nitrogen in the tires or not. They had the little fill caps that say "Nitrogen" on them so I assumed they were. But they do NOT show the same pressure all the time. Instead, they fluctuate 2 to 4 pounds based on the tire temperature. Like I said, my other car that did have nitrogen filled tires never did change. My bike also has sensors and nitrogen filled tires and it too doesn't seem to change either.

The TSB some have referred did not include my build date. Mine was built mid-June 2018.
 

Blackwing 55

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I just picked up a fully loaded Rubicon JLU. I took it on my first highway/Interstate short trip. The Jeep wanders a lot in the lane and the steering is vague and a little abrupt when correcting with lots of roll. I don't remember my older Jeeps driving this way.

So do I have an alignment / toe in issue or is this normal for these now?
I just picked up my new JLUR in Idaho and drove it 400 miles to my home in Wyoming including a rugged section of dirt road, because I am accustom to driving long wheel base pickups the steering did seem a little twitchy at first but it didn't take long to get used to it and now I love the way it drives, no complaints here !
 

Tykoehn1

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The dealer performed an alignment on my Rubi and it was slightly out of spec. After the adjustment it's still bad. They are ordered a new steering box because they believe it has too much slop. They didn't want to touch the adjustment screw. When they put the new steering box in, they are also goimg to maximize the allowable caster (5°).
 

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It is amazing to me that so many customers are picking up there JLs with over-inflated tires. Tires are over-inflated from the factory to reduce the tendency to flat spot due to the tie downs during the transportation process. It is part of the dealer PDI process to correctly set tire pressures, verify wheels are torqued properly etc. This process is mandated by FCA as well as all other OEMs. It seems that most dealers are just ripping off the protective covers, installing their dealer license frame and sending them to the wash rack to be delivered ... I made sure to note this on the survey sent to me after delivery ... most dealers live and breathe thru the KPIs and surveys
 

HardRock

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No. Again, this has nothing to do with tires or tire pressures. The guys dropping 3 PSI and claiming it fixes the problem are fooling themselves. It's almost funny. :cwl:

FCA is using at least 5 different tires on JL Wranglers. Goodyear Adventure A/T with Kevlar, Bridgestone Dueler A/T, Bridgestone Dueler H/T, BFGoodrich A/T KO2, and Michelin LTX M/S are all available. I have driven new JLs with at least 3 of those tires and they all exhibited the same wandering all over the road and required constant input into the steering wheel to remain in the lane.

This is a mechanical issue related to the steering box and/or programming for the electric motor that controls the box. Jeep is flashing the PCM which updates the calibration and this fixes the issue most of the time. Some guys have steering boxes that just come tight from the factory and need a few thousand miles to wear in. Either way, it'll all in the mechanical portion of the steering.

They'll get it fixed. It's just something we have to deal with during the first few months of a brand new model.
Yep. It’s oversteering. It’s to sensitive. The JK you can hold with your thumb and it holds its lane. The JL moves with a slight touch then you immediately have to correct it back then in the other direction again after that. Fatiguing.
 

bennettjames90

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Yep. It’s oversteering. It’s to sensitive. The JK you can hold with your thumb and it holds its lane. The JL moves with a slight touch then you immediately have to correct it back then in the other direction again after that. Fatiguing.
Took mine on the highway for the first time yesterday and it did that exactly. Oversteering like crazy, it was quite frusterating. Hope FCA comes up with a fix for this soon.
 

nova99

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So been reading this and other threads, including TSB research and here is my 2 cents. I traded/sold my 11K mile JLUR Hard Rock in that was in mint condition, drove like a new JKUR. Picked up a JLUR and drove concrete highways, rough city streets, and a gravel/dirt road on quick test drive before purchasing...Seemed fine. I purchased for my son so not my daily driver but on the way home from dealership the damn thing was all over the road (he was driving). Pulled over and same shitty steering for me too. Fortunately I had been researching and checked tire pressure while cruising at 70 and noticed tire psi was at 41-44 psi and different in every corner. Aired down to 36 psi on every corner and I drove it again today. 80 MPH down the same concrete, straight highway and it is like another vehicle. Perfectly straight and no fighting the wandering. This one has 450 miles on it now. Tire PSI is very important regardless of vehicle so I recommend people air down to ~36 psi and give it try. Good Luck
 

nova99

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It is amazing to me that so many customers are picking up there JLs with over-inflated tires. Tires are over-inflated from the factory to reduce the tendency to flat spot due to the tie downs during the transportation process. It is part of the dealer PDI process to correctly set tire pressures, verify wheels are torqued properly etc. This process is mandated by FCA as well as all other OEMs. It seems that most dealers are just ripping off the protective covers, installing their dealer license frame and sending them to the wash rack to be delivered ... I made sure to note this on the survey sent to me after delivery ... most dealers live and breathe thru the KPIs and surveys
My dealer will be getting a shit sandwich served to them via the All Mighty Dealer Survey as well. Report it enough and dealers will get put on notice.
 

JeepDrvr2018

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Not that I know of (charging for it). Nitrogen is also inert gas, meaning it is not supposed to expand or contract with temperature. I think that is why they started using it when they started putting sensors in the wheels. Compressed air also has humidity which under pressure condenses and makes moisture in your tires. In summer, that moisture can ruin the tire sensors. In winter it can form ice and rattle around in the tire. That's why I was asking.

Thanks
Hmm do we have any divers here. Have any heard of the bends? Gas, all gas expands when warmed or the pressure around a vessel (read tire here) lowers, hence the fact that nitrogen bubbles form in our blood, if we do not decompress on the way up from a deeper depth than earth standard. Have you ever had a bottle of soda, drank some, and then climbed up a steep hill increasing your elevation, and lowering the atmospheric pressure, the soda bottle will expand, try it with a bag of potato chips find one with a partially collapsed bag, unopened, see what happens when you go up in elevation about 1000 feet. When gas is put under pressure it heats up, friction also can cause this to happen, that is why our tires get warmer after driving them, and the pressure goes up as well. Try lowering the pressure to 33, drive 25 miles, my guess is the pressure has come up 2 pounds and they are very warm. When filling air tanks, they put them in a cold room, or in a tub of cool water to absorb the heat generated when they put couple thousand pounds of pressure in them. This may be an exception when preparing acetylene bottles, believe that is a chemical operation by adding two chemicals together to from the gas, not sure.
 

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