I installed a 2" OME HD lift last weekend on my 2010 Jeep JKU Rubicon. I am also running 17x9 Rugged Ridge wheels with the Fierce M/T's in 35". After getting done I went for a drive and noticed that there was quite a bit of sway at highway speeds. I drove another Jeep JKU with the exact same setup, with the exception of 35" Nitto M/T's, and it also had some sway to it, but not quite as bad. After comparing them side by side the sidewall on the Nitto is noticeably stiffer than the Fierce, which may account for some of the sway but not all. I've always driven trucks and suv type vehicles so I'm familiar with them having a higher center of gravity, but this seems like it's a little excessive.

When I installed the rear sway bar links I ended up with the end being at a slight downward angle, the front appears to be nearly level. After talking to Dave at Northridge I learned that they should both be about 5 degrees above parallel with the ground. I haven't adjusted them yet but I was wondering if anyone else has had this experience and was this all it took to get rid of the sway or are there some other things to look at like alignment, tire pressure, etc.?

As far as alignment it drives straight and does not pull to one side or another. Also, I got the adjustable front and rear track bars and the rear is offset by about 1/8th of an inch and the front is off by about 1/4 inch.

Side note here on a different subject, when looking at the regearing chart in the FAQ's, is the tire height being used with the tire mounted on the ground or reported diameter? My 35" is actually 34.8" but mounted on the ground it's 33.75".

Thanks in advance.

 

What pressure are you running in the tires? If it's over 28 or 30psi, drop it and do a chalk test to fine tune.

You should have gotten a bit over 3" with those coils? Open the FAQ's, in the suspension section read the one on Caster and see if that is what you are feeling. (that's my guess, since I didn't see any mention of adjustable control arms).

Your axles being off-center is normal after a lift. Since you have adjustable trackbars front and rear, all it means is that whoever installed them didn't bother to center your axles.

What you were told about the swaybars pointing up is correct, but having them pointed up or down bit, or level, should not cause the sway. When you flex offroad, short links (swaybars angled down) may cause the the swaybar to flip around backwards, which creates a great photo op.

Use the actual mounted height with the tire at normal pressure and sitting under the full weight of your jeep. Not the mfg's spec, not the sidewall spec, not the spare.

 

So I make sure I address all of those points;

1. Apparently the tire shop decided I needed 38-39 psi in my tires, so that may be a big part of this. I will know how much this affects it tomorrow night when I get home in time to lower the pressure and drive it again.
2. I wouldn't say it feels flighty or darty, I would say that it feels like a waterbed sloshing around.
3. Are the slight offsets in the axels going to make any difference in handling? 1/4 and 1/8th don't seem like much.

4. Reference the tire question then I'm in that "personal preference" 4.88/5.13 twilight zone with an auto..... great

 

Yep, it seems pretty normal for tire shops to over-inflate. I bought at Discount Tire, and every single time I go in for the free balance/rotate they pump the tires up to 40lbs or so. (unless I stand out there and specifically ask the tech not to.)

lol, the only thing I can think of is very tall tires on very small rims with a ton of sidewall flex. Not the case for you, just the only thing I thought of.

Did you happen to install a front trackbar bracket as well as the adjustable?

The axle offsets should not make a big difference. I didn't have any issues when mine were off a bit, I got rid of the small offsets just because I kept noticing it...

And yes, the gear ratio is definitely personal opinion. I am one of the "don't fear the gear" people who went from 3.73 to 5.13 to 5.38. And my tires are a bit shorter than yours.

 

Did you happen to install a front trackbar bracket as well as the adjustable?

I installed the front and rear adjustable JKS trackbars, I didn't get a bracket and one was not mentioned.

The axle offsets should not make a big difference. I didn't have any issues when mine were off a bit, I got rid of the small offsets just because I kept noticing it...

I'm sure I'll become self conscious and start staring at it too eventually.

And yes, the gear ratio is definitely personal opinion. I am one of the "don't fear the gear" people who went from 3.73 to 5.13 to 5.38. And my tires are a bit shorter than yours. [/QUOTE]

Since going to the larger tires I can tell I will need to change the gears by the end of next year. Next month will be my second vacation to Colorado. I know the Jeep was huffing and puffing on the factory wheels and gears last year, I can only imagine what's going to happen this time. I'll just have to drive in the truck lane, lol. That's part of my debate also, I go to Colorado once a year, the rest of the time is spent on the flat part of kansas. Did your MPG's get anywhere near stock with 5.13's?

 

Mpg's are a bit better with 5.38s than the 5.13s, the theory is that I am staying in OD longer before downshifting.


See post 4 for a recent trip. Still scratching my head.
(4door auto, somewhere around 4" lift, 5.38's, 35's (33.5" actual height)
https://www.jk-forum.com/forums/show...9-affect-MPG-s


On the way back, I was loaded down with a treadmill and misc gear inside, and towing an 18' ski boat with more crap thrown in it.
Texas - 10-11mpg doing 65-70
Colorado - 13-14mpg doing 70-75

 

Yeah, but you're running 37's and 5.38's AND you live in Colorado where that's probably ideal. Around Wichita there are the occasional slow rolling hills but for the most part it's pretty flat, so I don't want to get real crazy. They raised the interstate speed limit to 75, so I'll probably drive around 80. 80 with the 32's and 4.10 was running around 2500 rpm, if I switch to 5.13's I'll be running close to that at 70 on 35's....... then I'm afraid I'll be down in that 12 mpg range. I know I know, it's a rolling brick and no I didn't buy it for gas mileage, but when I take those long trips to Colorado and such I don't want to be stopping at every gas station. I would at least like to be back in the 16-19 range on the highway.

BTW, I'm going through Pueblo, Silverton, Marble and leadville, any places I really need to see along the way? That route is flexible since I'm not sure what might distract me along the way, but I would like to make it to Silverton and Marble. Last year i was in Leadville and Colorado Springs and enjoyed that.

 

Thats about the same mpg i get too

 

Don't forget that when in CO you are at higher elevations. Everybody talks about the reduction in power, but don't talk about the other side effect...better MPG. Depending on altitude, there is definitely less O2, so the computer has to cut back on fuel to maintain a proper air/fuel ratio. Power output drops, but MPGs can go up (if not offset by having to drop to second gear and scream up the mountain passes! ) Also, when you're driving a brick like we are, wind direction and speed can also cause huge variations in fuel economy.

All that to say...the better MPG one poster experienced in CO vs. TX was not just a result of gearing (that helps, too), but also the result of less fuel being burned due to a less oxygen being available per cubic foot.
Chris

 

I can only imagine how much my 3.8 is going to be screaming this September, I'm sure I'll be up to 10-11,000 ft anyway and some of those roads are pretty steep. With 35's and 4.10's it will be interesting. Oh well, I'm there for the scenery and to be on vacation, not to rush around with my hair on fire.