JK: I Screwed Up

[TipsE-Z]

I drove a 2013 JKU Rubi with a 3" MOPAR lift and 35s... We haven't bought it yet, but man we are hooked.

I do have a question for some JKU folks... Is a 3" lift enough to give you a decent break over angle or is a 6" a better route to go? We're looking for some 2012 Rubi's right now that are done (their loss, our gain). Any thoughts?

[inVERt'D]

The ride is quite a change from the YJ, isn't it? I'm not sure if I qualify as "JKU folk," but I had use of a stock '08 Rubi Unlimited for most of a year--and I wheeled it.

Thought 1: it was nutless on the highway with 32s. Engine needed more power and the gearing sucked. Shift points sucked. In fact the auto tranny was a total slushbox. Hated it with a passion at times. Don't take it from me, I don't like auto trannies.

Thought 2: the turning radius is not all that great.

Thought 3: obviously how much breakover angle you need depends upon the circumstances. There were times on the stock Rubibus the lack of breakover angle was problematic. There is an annoying crossmember aways behind the front wheels that was apparently designed to catch on things, and things like that didn't help. The plastic charcoal canister is underneath the passenger area, and is vulnerable. I broke it . When I could avoid tackling obstacles in ways that required good breakover angle, the Rubibus performed very well. At times very favorably compared to a SWB Jeep.

How's your YJ's breakover angle working for you? For comparison, calculate the current BOA for the YJ, (or what you'd like it to be) then use that as a starting point for you JKU BOA. Figure what tires you want to run (37s will kill the front axle), and how high you need the belly to be to achieve your BOA on a 116" WB, then you can derive how much suspension lift you need.

Thought 4: just in case you haven't stumbled across the following info...
The JK front Dana 44 is not very strong. The axle tubes are the same skinny affair as the YJ and TJ had on the D30 and D44 fronts, but they're wider. Having more leverage against those skinny tubes makes them prone to bending with hard use and/or big tires. You can sleeve the tubes and gusset the inner Cs to help overcome this. The rear JK D44 is significantly stronger than the TJ's. The axle tubes are the same IIRC, but the gears are much stronger, and the axles are 32-spline.

Thought 5: you're a robotics engineer???? I HATE you! Just kidding. Seems like a great field to be in right now--maybe the last one Got some AI and ML tech. Need to mess around with PLCs.

[mkjeepers]

The general rule for the JKU to make it usable as an all around off-road vehicle is 4 1/2" suspention lift and 37" tires. The motor and trans as well as the gearing has been improved on the 2012 model. If you're going to buy, I reccomend the 2012 over any earlier model.

[6spdYJ]

The axle tubes are the same skinny affair as the YJ and TJ had on the D30 and D44 fronts, but they're wider. Having more leverage against those skinny tubes makes them prone to bending with hard use and/or big tires. You can sleeve the tubes and gusset the inner Cs to help overcome this. The rear JK D44 is significantly stronger than the TJ's. The axle tubes are the same IIRC, but the gears are much stronger, and the axles are 32-spline.

The JK rear 44's tubes are a beastly 3 1/4" with the same pinion bearing diameter as a D60, an 8.9" ring gear. You won't go wrong with this setup. The TJ 44's had the same tubes as the D35.

[inVERt'D]

The JK rear 44's tubes are a beastly 3 1/4"

Is that right? The TJ's are 2-5/8 (I know it well by now). I stand corrected!

[mkjeepers]

The JK's have the second generation D44's on the rear - on both the Rubi's and Sport/X models.

[inVERt'D]

Yeah I understand they phased the Dana 35 out after 2007. What a shame.

[Tumbleweed13]

The 3.6 Penstar engine, they changed over too, in 2012, was originally design, for a turbo. The overall engine has stronger internals, and puts out more power. The old 3.8 would let go, after alot of wheel'n with big tires. Definitely get a 12 or 13.

[mkjeepers]

The 3.6 Penstar engine, they changed over too, in 2012, was originally design, for a turbo. The overall engine has stronger internals, and puts out more power. The old 3.8 would let go, after alot of wheel'n with big tires. Definitely get a 12 or 13.

The new change for 2012 and up is the Penstar motor (285 hp) with a MUCH, MUCH better 5 speed auto trans that can also be shifted manually. Can't wait to get mine back from the body shop, after smacking the side of a lady that pulled out in front of me.

[TipsE-Z]

Thanks for the input folks! We have begun our search but I doubt we'll get it until after Christmas unless a smoking deal shows up on one that is built the way we now hope for. I'm looking for something that has some skids added, bumpers, sliders, 4-6 inches of lift and 35s. I'm not too keen on the 37s, I'd rather give the suspension plenty of room to move. We drove a '12 and an '09 and we could really tell the difference on the 12; that's for sure the way we are going to go. Guess I need to clean up my YJ and get it ready to be sold.

[Ol Man]

Just for information, I have only a 1 3/4 Daystar lift on my JK and run 35 inch MTRs. You do not need to go 4-6 inches of lift, unless you plan to go to 37s.

[TipsE-Z]

I've read and been told that you can get away with 35s on a small lift with them, and one we test drove the other day only had a 3 inch lift with 35s. But when we took it for a test drive and flexed it out a bit I was a little concerned that in some extreme flex places the up travel tire might rub or bury in the inner well.

[Ol Man]

I've read and been told that you can get away with 35s on a small lift with them, and one we test drove the other day only had a 3 inch lift with 35s. But when we took it for a test drive and flexed it out a bit I was a little concerned that in some extreme flex places the up travel tire might rub or bury in the inner well.

I run the GenRight aluminum fenders. On the front of the rears, I took my 4 inch and removed a little body metal to the shape of the fenders. It may hit slightly, but no big deal. No issues at the front.

With the 1 3/4 lift, I did not have to change shocks and maintained the stock ride. The Rubicon shocks are OK.

Good luck with your search.

[SoCalinIt]

I have just over 4" of lift on 37" tires. I run bump cans, and have flat style fenders on mine. I had to trim a little, but nothing too much. My friend runs a budget lift with a little bit bigger bump stops and has no issue with rubbing. He ended up with stock cut fender flares too.

I have the Poly Performance coil over kit, and the Rubicon long arm kit. I added Poly's bump can mounts, and steering setup. It works well. The motor in my 07 is crappy, and lacks a lot of power. I did the cat back exhaust, throttle body spacer, intake, Jet chip, programer, and 5.13 gears. It has as much as it's going to get.

The new motors are way better, but really... it's a Jeep. I'm not driving 80+ mph in it.

My .02

[TipsE-Z]

The new motors are way better, but really... it's a Jeep. I'm not driving 80+ mph in it.
My .02

That's sort of my thoughts too; but if I'm going to take on a car payment I might as well get the newest I can afford. As of the moment we are still in the early stages of our search, and getting the YJ ready to be sold in the coming month or so. Yes... I will be Jeepless for a bit. :censor::bonk: