2006 Jeep Wrangler LJ Rubicon Long-Arm Suspension - Four Wheeler Magazine

2006 Jeep Wrangler LJ Rubicon Long-Arm Suspension 2006 Jeep Lj Rubicon front Drivers Side View Photo 9191950

When it comes to trail rigs, the Jeep Wrangler Rubicon is about as good as it gets from the factory. And with the added wheelbase and cargo space available in the Unlimited version, you get a rig that can both climb better and carry more gear than any of its siblings. Not a bad place to start, if you ask us. That's why we decided to borrow a brand-new '06 LJ Rubicon and deck it out with all our favorite essentials in aftermarket suspension and drivetrain upgrades. Follow along as we take Jeep's best-to-date to new heights. Special thanks to the wrenches at Train's 4x4, who can transform just about any vehicle from showroom-stock to trail-boss in just a day's time.

PhotosView Slideshow Maybe Jeep should have called them "Flexicons" instead. Right out of the box, the Jeep Rubicon Unlimited outflexes just about anything on the road. Ours scored an impressive 607 on our 20-degree RTI ramp. However, with just a few slight tweaks (disconnecting the antisway bar and lowering tire pressure) we were able to gain a few more valuable inches, pushing our RTI score to 637. This is the Rubicon Express (R.E.) LJ 5.5-inch five-bar long-arm suspension system we ordered. All the parts came packed in boxes that were both clearly marked and well-isolated with packing material to ensure a trouble-free install. Rubicon Express has been designing and manufacturing Jeep suspension and performance parts for well over a decade. Because of the close proximity to the Rubicon Trail, all of its components are well-tested for trail durability and on-road worthiness. Some noteworthy features include 4130 chromoly control arms, serviceable Superflex Joints and Grade 8 fasteners. Here, you can see how the axles are supported under the Jeep; note the new bumpstop extension installed on the lower spring pad. With the Jeep secured on a lift, the shop's owner, Mark Train, removed all the factory suspension components. Once this was completed, he then proceeded to remove the factory lower control-arm mounting brackets from the frame. During this process, Mark took a great deal of care to prevent cutting into the framerails and fuel lines. At first a plasma cutter was used, then a 6-inch grinder was used to clean up the edges. This photo demonstrates the difference between the Rubicon Manufacturing's Extreme Duty monotube shock and the factory units. R.E. tunes these shocks specifically for each application to deliver maximum control while not compromising ride quality, high-speed stability, or comfort. We like these shocks because they feature good-sized (46mm) metal velocity-sensitive pistons and solid nitro-steel piston rods. No chrome to chip or peel like other shock shafts. Additionally, these units are U.S.-built and feature Viton seals, robotic welds, a durable powdercoat finish, and they are available with remote reservoirs. Oh, and they come with a lifetime warranty. Next, the factory bellypan was removed to gain access to the underside of the framerails. Each rail was marked and center-punched for accurate drilling. The new R.E. bellypan requires two 1-inch holes on the bottom of each framerail. Here, Mark is starting one of the 3/16-inch pilot holes. PhotosView Slideshow Six 3/16-inch pilot holes were drilled through both sides of the framerails. Shortly afterwards, the holes were enlarged on the inside of the frame to 1/2 inch. The pilot holes on the outside of the frame were then hole-sawed out to 1 inch to accommodate six billet frame spacers. The spacers, once welded in place, serve as sleeves for six through-bolts that secure the new bellypan's outer brackets to the framerails. The secret of the R.E. long-arm kit that makes it perform well is the positioning of the upper and lower control arms and mounts. Designed specifically to enhance vehicle dynamics both on and off pavement, the math used here makes all the difference in how the long-arm kit controls pitch, yaw, and sway. The correct amount of anti-squat and carefully calculated suspension geometry help to minimize body roll and improve on-road handling dynamics, while the range of motion is maximized to aid articulation. Note how flat the bellypan is once installed. No protruding bolt heads to get caught on rocks-just flush, flat, and smooth. This photo shows how the rear lower control arm connects to the bellypan. Shown are the massive rebuildable Super-Flex joints. Rubicon Express ran a whole season in the competitive Jeep Speed racing series with the same type of control arms-with zero failures. At the end of the season, they were as tight as the day they were installed. In contrast, other Jeep Speed teams who use factory rubber bushings typically have to replace them after every race. This is the lower track-bar bracket extension R.E. includes with the system. The instructions say to simply bolt this bracket to the existing track-bar mount with the supplied hardware, effectively raising the lower mounting location by about 3 inches. However, we opted to weld this bracket to the existing mount in addition to bolting it as the instructions suggest because it's been our experience that these brackets experience high stress loads during articulation. A slightly longer CV front driveshaft was required up front, so we contacted JE Reel of Pomona, California, to get a new shaft built to our specs. The new shaft featured JE Reel's new waterproof U-joints, which are designed to handle increased torque loads while requiring less maintenance than standard U-joints. Thanks to their specially designed seals that remain effective through a greater range of temperature, these unique joints are not affected by water and are said to last much longer than OE units. They also come with special waterproof grease that is rated for extreme pressure and high temperature. Forged from high-strength alloy steel and then cryogenically treated to increase durability by about 40 percent, these joints are so tough that J.E Reel has a lifetime guarantee against breakage. We decided to install a set of JKS Manufacturing's adjustable coilover spacers commonly referred to as the "ACOS" system. The ACOS system allows the end user to fine-tune his or her suspension system to accommodate for variables such as the added weight of bumpers, winches, and cargo-effectively leveling the vehicle front-to-back or side-to-side. The ACOS does add about 1.25 inches of lift but allows an infinite adjustability thereafter. Because our donor Jeep already had Hanson bumpers, a winch, and a removable hardtop, we felt this system would best accommodate any variances in ride height. PhotosView Slideshow As you can see, the ACOS spacers also look sweet once installed. We don't recommend running 37-inch tires on a stock Dana 44 front axle, especially in rockcrawling applications. As such, we upgraded our donor Jeep's front axle with 4.88:1 gearing from Yukon Gear, a pair of chromoly inner axleshafts from Alloy USA, along with 300M replacement U-joints from Longfield Super Axles. These axles are much stronger than stock, and the new Longfield joints come with a lifetime guarantee against breakage. We like them because they're less expensive than other high-strength U-joints on the market while still maintaining superior strength. The Alloy USA shaft upgrade comes with Spicer 5-760x U-joints, but we felt the Longfield joints were a better choice for this application. It's true this upgrade would theoretically move the weak link to the ring gear, but for now we want to see how well all these upgrades live before taking the next step: cryogenically treating the ring-and-pinion (we'll delve into that some time down the road). The good folks at Right Gear and Axle of Salinas, California, did the gear and axle swap for us in a short afternoon visit. We also decided to upgrade the rear Dana 44 axle with 4.88:1 gears from Yukon and dual-pattern Alloy USA axleshafts to ensure we wouldn't have any axle issues. These shafts are made from a higher-strength alloy that is double heat-treated to produce a 35 percent increase in strength over stock shafts. We also like that these shafts come with a 10-year warranty and include bearings, seals, and wheel studs. 2006 Jeep Lj Rubicon left Front Tire Photo 9192070

For wheels, we picked a nice set of 17x9-inch aluminum Walker Evans bead locks for this project. These wheels are one of the best values, dollar for dollar, in the cast wheel department. Designed to survive the rigors of Baja racing, these wheels came in an attractive polished finish, with all the appropriate Grade 8 bead-lock ring hardware.

For traction, we chose the competition-proven 37x12.50/17 BFG Krawler. These tires are legendary among rock racers, and because our donor Jeep's owner was planning on towing his rig most of the time, we figured the Krawlers were a good match. The tires were mounted and balanced by California Automotive and Tire of Salinas, California. Additionally, the folks at Right Gear and Axle provided a Warn premium hub conversion kit and installed it for us at the same time they did the gears. This system is a must-have for anyone planning to do any serious trail work in a Dana 44-equipped TJ/LJ. We made this conversion to our own project Teal-J II (Oct. '05). The kit adds valuable girth to the OE stub axles as well as increasing the lifespan of all front drivetrain componentry. We also noticed a slight improvement in highway fuel economy with the kit installed while running stock tires and wheels.

2006 Jeep Lj Rubicon underside View Photo 9191998

Just as we were going to press, Rubicon Express released a new tri-link option for the LJ long-arm system. This kit changes the rear upper control-arm mounting locations (and geometry) so as to allow removal of the rear-axle track bar. R.E. spent countless hours developing this upgrade to ensure proper handling characteristics in all driving scenarios. One of the advantages of tri-link rear suspension is increased freedom of movement that allows the axle to respond to the terrain better. This is an advantage when rockcrawling at low speeds and also at high speeds, such as when blasting up a desert sand wash. The disadvantage is an increased roll center, which gives an effect similar to a high center of gravity.

We had the opportunity to drive and wheel an LJ equipped with the Tri-Link system in Moab. We liked the way it worked on the trail better than the standard five-bar system. On the road, the Tri-Link was the best driving tri-link suspension system we've tested, though as previously mentioned the handling characteristics inherent with tri-link suspension systems contributed to more body roll than we felt comfortable with for an everyday driver. That's not to say we wouldn't drive it on the street, it's just not the kit we'd install on our teenage daughter's commuter Jeep. In closing, we found the Rubicon Express Tri-Link kit handled just as their marketing department said it would. The slight on-road handling disadvantages will be well worth the increased off-road performance for most customers.

2006 Jeep Lj Rubicon front Drivers Side View Photo 9192079

Luckily for us, our donor Jeep made it out to Moab this year for the annual Easter Jeep Safari gathering. We're happy to say the suspension worked flawlessly, as did the drivetrain upgrades we installed. However, the two areas we failed to address in this build did in fact fail; steering and the rear ring-and-pinion. Our owner found out the hard way that even though he upgraded to a Teraflex crossover high-steer conversion shortly before Moab, the OE steering box was not at all willing to push around 37-inch rubber in the rocks, making quick work of the Jeep's OE sector shaft on Moab's Green Day trail. Luckily, Pat Gremillion of Premier Power Welder was there to lend a helping hand so we could continue our suspension testing. In the future, this particular Jeep will receive a ram-assist steering upgrade to help relieve the additional steering force.

Later in the week, on Golden Spike trail, our test mule broke a rear ring gear trying to climb a 3-foot ledge. Needless to say, cryogenically treating the ring-and-pinion is in the near future. Otherwise, piloting this Jeep on the trail was pretty much a point-and-shoot affair. On the road, the vehicle felt much smoother than stock, and the RTI scores with and without the addition of a Currie Anti-Rock sway bar were much more impressive (907 with the Anti-Rock connected).