Rubicon Express Extreme Duty 5.5” TJ Lift Kit
By Chad Crowell


First Few Days

Take a look at the amazing clearance you now have! We immediately measured the height of the Jeep:

  Before After Gain
Bottom of front bumper 24.5" 28" 3.5"
Bottom of rear bumper 24" 28" 4"
Bottom of crossmember 16.5" 20.5" 4"

BEFORE: Click for larger picture.
BEFORE: Click for larger picture.
AFTER: Click for larger picture.(Remember, its 1 inch lower due to body lift removal)
AFTER: Click for larger picture.(Remember, its 1 inch lower due to body lift removal)

The height difference is incredible. Allowing for some break in, the height gain should be about 2” over the 4.5” kit. Keep in mind with these after pictures that I removed the 1” body lift in between installing the rear end and the front end. The above measurements include 1” for the body lift.

Rubicon Express provides a dropped pitman arm to help with bump steer. The angle at which the drag link and track bar operate should be equal, or very close. Rubicon Express states that the modified geometry of the new track bar bracket requires a drop pitman arm to eliminate bump steer. They also say that with this increased lift height, in some off-road situations the factory tie rod ends will be over-extended and could be subject to increased wear or failure.

Without installing the pitman arm, my angles are very close, and after driving it I feel no bump steer at all. I will not be installing the new pitman arm. Your results may be different. The pitman arm is notorious for being a pain to get off. You may want a 4x4 or transmission shop to replace it for you.

It was nice to have a quiet suspension again...new bushings and joints make all the difference. Check out the clearance under the front fenders, no rubbing with 35" tires.

I also found that at full lock, my tires were rubbing my Currie AntiRock links. I had to place a few washers under the steering stop in order to keep this from happening. Unfortunately, this will lessen your tight turning circle, but it is the safest way to avoid this type of rubbing.

Before driving the vehicle, be sure to go back and double check all suspension hardware, jam nuts, and clearances. Take a test drive and see how plush it is. Go off a curb or two, or over a pothole…the suspension reacts very nicely. Listen for any strange noises and feel for any out of the ordinary quirks. Adjust as necessary. Also set your toe-in and steering wheel alignment.

Now take it on a real test drive, gun it, brake it, turn it, bump it…I was extremely pleased with the results, even before the springs had a chance to break in! What was interesting was that it finally helped me realize how to describe the feeling the old lift gave me as well. Its not that the new lift makes the bumps feel smoother, its that you just don’t feel them. Small bumps are completely absorbed by the suspension, and larger bumps feel small.

Another good shot of the front fender clearance. One side stuffed, one side stretched. There is still plenty of room all around the long arms.

The TJ does not squat when you stomp on the gas. The entire vehicle simply moves forward. Side to side movement is predictable. The Jeep leans in corners, to be sure, but it feels no different than it did with the 4.5” lift. I always thought the TJ cornered very safely with the old lift and feel the same now. Even with the AntiRock, which allows more body roll than the stock swaybar, it is solid when taking corners at reasonable speeds.

Highway driving is free from coil spring cycling. Ever hit a large bump with the 4.5” lift? Some people call the result ‘Death Wobble’…and it is not fun. I can’t reproduce the effect with this lift. Thank God. And what of the tire pick issue? Again, I can’t make it happen now. Fine with me.

Overall, after driving the Jeep for a week, I am very impressed with the results. The Jeep is comfortable and stable. I can feel the springs breaking in already, so I expect it to only get better. I also found that I can sit up completely straight under my rear axle and not hit my head on the tub floor. I am 6’1”. Cool.

Impressions - Off-Road

Over Thanksgiving I took the TJ up to Bassi Falls, near the Rubicon, to test out the suspension off-road. I have yet to get the track bars completely adjusted to center the axles under the Jeep, but that did not come into play.

The only issue that did concern me was the Tomken gas tank skidplate hitting the rear track bar bracket. I decided to let it go for this testing trip, and there were no ill-effects. I will be cutting up the skidplate a bit to allow more clearance in the next few weeks.

So how did it perform? Quite well I must say. The extra clearance under the entire vehicle was noticeable. Having been to Bassi more than a few times, I attempted obstacles that I knew, and found that many of them could be navigated now without scraping a rocker panel or the gas tank skid. I have yet to use the long arms as a “rock slider” as some would suggest, but I am sure that will happen before long. I have full faith in the arms to support weight as they are ” thick 4130 chromoly tubing.

A view of the front end from underneath. Again, one side stuffed and the other stretched. With the Antirock disconnected, I found that the front axle drooped only about 3" more.

The suspension itself felt amazingly similar to the old 4.5” kit. What made a difference was the Currie AntiRock. More on that in a future article. I wheeled for a bit with the AntiRock disconnected and really felt confident with the feel of the TJ. It lived up to the off-road reputation I have come to expect from a Rubicon Express kit.

One item that may need to be addressed is the cut-out on the new crossmember for the driveshaft. While thoughtful, the cutout needs to be a little wider. Here you can see a brand new score on the shaft from the edge of the crossmember. Perhaps another ” on each side would help. Of course, this may not be an issue once my axle is 100% centered. Otherwise, I looked at every piece of the suspension at every angle and found no clearance issues at all.

The best part of the whole trip was the ride home. After stretching and stuffing the springs while playing on the rocks, they broke in and softened up even more. The ride home was smooth and relaxing.

The front driveshaft hit the skidplate at some point. Notice the mark on the shaft. Even with the rear swaybar connected, there was plenty of droop in the rear.


Rubicon Express has done it again. I have always spoken well of the 4.5” kit based on my good experiences with it, and at this point, I must speak well of the long arm kit. As promised, the road ride is much better than with the 4.5” kit.

The new suspension geometry allows even taller springs to be used, yet the Jeep still feels stable and not top-heavy. Bumps are felt as with any vehicle, but the difference is very noticeable. Corners are not scary, provided a safe cornering speed is used (No one should be driving a tall Jeep around like a CRX anyway).

Off-road, performance is at least equal to that of the older lift kit. Combined with the Currie Antirock swaybar, the 5.5” lift is spongy, yet predictable on climbs, side hills, rocks, and ledges. And knowing how your Jeep will react when you drive it is part of being a good driver.

The rear end had no clearance problems. Even the exhaust turned out to fit ina ll the right places. Another good shot of the long arms.

The final question is value. Is this worth $2500? After all, I was a prime candidate to simply change out a few components and be happy for another few years. And I was also quite content with the on and off-road performance of the old kit.

If you are starting from scratch, absolutely, yes, buy this kit and you will have excellent results. But remember, you can also start smaller and upgrade to it later as your Jeep grows.

I can’t help but say that if you have the 4.5” kit, and don’t have a specific reason for the upgrade, you should stay with what you have…or perhaps buy just the long arm upgrade to improve your road ride. Changing out the entire kit is not necessarily worth another $2500.

However I am glad I did it, as I have ridded myself of the demonic heim joints and have the newest technology and hardware available. While I am sure improvements will be made, I will surely be able to use the TJ comfortably and reliably until the next big trend in TJ suspensions comes to light (adjustable magnetic field “springs”, anybody?).

The front trackbar bracket does not interfere with the suspension at any point. A view of the entire underside skidplate and long arms.

Intro | The Plan | Skidplate | Rear End | Front End | Impressions

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