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Rubicon Express Extreme Duty lift kit for Jeep TJs
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Finally! A tall lift for TJs that really works! Short Cuts

By: Paul Nasvik - 5/2000

On the Rubicon

Since going to 35 inch tires, I've been unhappy with the way my TJ handles. It's been squirrelly on the road, and unstable on the rocks. I was planning on a custom suspension with longer control arms. Then I heard a rumor that Rubicon Express was playing with that idea, so I called them. A kit was almost complete and ready for sale. "Almost" meant 2-3 weeks. If you've ever waited for new parts, you know that 2-3 weeks can seem like a long time. In this case it was 8 weeks.



Was it worth it? Absolutely.

Rear components
Rear components
Front components
Front components

If you already have a suspension lift, there's an upgrade option. The upgrade kit comes with:

I ordered the complete kit. In addition to the parts above, it came with:

This kit is not a complete solution - it doesn't address driveline angles so you'll have to work that out with an SYE kit. You will need a slip yoke eliminator and CV driveshaft to run it. If you have an Atlas transfer case, don't worry - the skid plate is compatible. If you've swapped in a transmission, the skid is available in pieces - weld to fit and paint.

I installed the lift using basic hand tools and the following:

Installation took a weekend working at a casual pace. If you move quickly, I would guess 8-9 hours. Bear in mind that I've installed many lifts on TJs and didn't run into any problems. RE's instructions recommend a factory service manual. A solid understanding of your Jeep's underside is recommended before starting this installation.

While Rubicon Express calls this a bolt-in installation, this kit calls for drastic measures. You have to cut the stock control arm mounts from the frame, drill ten 1" holes in the frame and you may have to relocate your rear shocks to clear the spring pad. RE gives you the option of (and recommends) welding the sleeves in the 1" holes you drill in the frame.

I'm not going to go into step-by-step instructions, but here are the basics:

Drill 1 3 more holes on each side. Remove stock control arm mount.
After removing the stock skid plate, drill two 1" holes in the bottom of each frame rail. Then drill 3 more 1" holes in the side of each rail. Here you see the frame painted and sleeved. Remove the stock suspension, then remove the control arm mounts from the frame.
Install the new crossmember. Install rear suspension components. Install front suspension components.
Install the new crossmember/skidplate using all ten (!) bolts. Install rear control arms, track bar bracket, track bar, sway bar links, brake line, springs and shocks. Install front control arms, brake lines, springs and shocks.

Testing

The first thing I noticed about the new ride is this Jeep is TALL!! The kit added over 2" to the height of my Jeep (it has since settled to 1.5"). At 6'2", I'm starting to have a hard time getting in it. I have heavy bumpers, a winch, a full roll cage, a Kilby Rack and no problem clearing the 36" Super Swamper tires.

The first drive on the road was strange - I wasn't used to my Jeep behaving this well. When I let out the clutch, the Jeep goes forward - no squatting. When I turn the wheel, the Jeep turns with almost no body roll - that's with the Currie AntiRock on the flexiest setting. When I turn the wheel to the left and punch the gas, the front left wheel doesn't come off the ground like it used to.

The clearance under the skid plate is 1" taller than with the stock plate. Anything is possible, but it would take a lot of careful planning and modification to raise it any higher. Would it be worth it? I don't think so - the Jeep is tall enough it shouldn't matter. I now have 21" of clearance under the plate.

I can let go of the wheel (carefully) on the freeway and it not only tracks straight, but it doesn't bounce all over the road. This was enough to inspire me to finally hook it up behind my Ford and tow it to the Rubicon. I had no problems and it tracked right behind me all the way to the trail.

After setting up base camp, I took the Jeep out and did a little testing. The only problem I encountered was the rear brake line - the control arm hit it when compressed. This was my fault and easily fixed by bolting the bracket in to the frame instead of the stock control arm mount..

I also found that the shocks are the droop limiter in the rear. I'll relocate the shocks, change to shorter swaybar links or add limiting straps.

The next morning we set off hoping to make Spider Lake. This was a good test for the suspension, as there was still a lot of snow on this already difficult trail. I had plenty of opportunities to test the flex and stability. I took the Jeep over every obstacle I could find - not once did I feel out of control. There have been two types of obstacles that have caused me to back off: very steep slabs and off-camber to the right while climbing or turning left. Both situations lift the front left tire high off the ground. I did everything I could to make it happen again, but the Jeep stayed balanced and kept moving forward.

Because the long control arms are almost level, the front end climbs obstacles instead of burying itself against them - great for crawling up ledges. When off camber, the Jeep stayed stable. Twice, I slid sideways into a snow filled ditch while off camber and didn't bounce onto my side.

The Jeep still flexes well. Steep slabs are not a problem. The Jeep stays level.
A quick ramp test (in 2wd) to make sure nothing is binding. It doesn't lift a tire on steep climbs anymore. All four corners feel well balanced and keep the Jeep level.
A view underneath. A little off camber. Flexes well.
Some clearance was lost, but it's not as bad as I thought it would be - I only scraped a couple of times and just barely. It's very tall, but still stable in off camber situations. The joints on all 8 control arms allow the axles to move freely.

Conclusions

Rubicon Express has delivered on its promises: the Extreme Duty kit is great on the street and on the trail. Installation takes some time and will be hard to reverse, but it's worth it.

The only trade off to the lift that I think matters relates to maintenance. Removing the skid plate will add about an hour of work to a transmission or transfer case fluid change.

I was worried about the clearance under the control arms and skid plate. I scraped the arms a little on the trail, and completely missed the skidplate. The Hammers and similar trails will most likely add gouges, but everything scrapes on that kind of trail. The amount of control is worth a slight loss in ground clearance. I'm hoping that the long control arms act a bit like sliders - the stock control arm mounts hang up on everything.

I don't think it would be possible to make the cross member sit much higher without major surgery. The control arm bolts are hard to get to the suspension geometry makes me think that the clearance gains wouldn't be worth the loss of control on the freeway.

Besides...if you really want more height, go for 38" tires - there's room and the suspension can handle it.

Contacts: Related Links:

  • The Rubicon Express press release.
  • Brad Kilby's TJ-7 - another approach to a tall TJ.





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