Rubicon Express was one of the first suspension manufacturers to offer a long-arm lift for the ’07-present Wrangler chassis with its Extreme-Duty Long Arm. The system worked great, and given how many JKs on the trail were running them, you’d think it was a factory-installed option. But regardless of its popularity, the Extreme Duty’s radius arm design drew criticism from those who wanted a true four-link suspension with upper control arms completely independent of the lowers. Not too long ago, Rubicon Express unveiled its first true four-link long-arm suspension system for the JK Wrangler, the 4-Link Extreme-Duty Long Arm.
Like the regular Extreme-Duty Long Arm, the 4-Link Extreme-Duty system is designed and intended as a high-performance cohesive suspension that works with all the JK’s electronic stability controls to deliver a predictable on-road ride without compromising off-road capability. The control arms’ and track bar’s heavy-wall chromoly tubing and the high-misalignment Super-Ride bushing and Super-Flex joints deliver a quiet ride and substantial flex with no drawback to on-road handling. The kit use a full-width, heavy-duty transmission crossmember to locate the front lower links and bolt-on frame brackets for the other control arm mounts. There’s no welding required. Despite the bolt-on design of the system, it’s not something that goes on easily in an afternoon. The installation of the Rubicon Express 4-Link Extreme-Duty Long Arm is quite involved and best left to a very experienced enthusiast or competent off-road shop.
We brought our well-worn ’07 Rubicon and two pallets of Rubicon Express product to AOE 4x4 Industries in Laguna Hills, California. With a tired set of 35s on factory wheels, wheel spacers, and a simple budget boost coil spacer lift, our test vehicle was otherwise stock.
We had access to a mildly modified ’07 Wrangler Unlimited whose owner was ready to take it to the next level. Having gotten by with little more than an inexpensive coil spacer lift and some worn 35s on stock wheels, he was tired of the lack of uptravel and harsh bottoming when exploring the trails and back roads of the desert Southwest. The 3.5-inch Rubicon Express 4-Link Extreme-Duty Long Arm promised a solution. Because we were upsizing our order to Rubicon Express with the optional front and rear double cardan driveshafts with 1310 U-joints, front T-case output shaft yoke, and optional Rubicon Express High Steer Kit, we knew we were better off leaving the install to the professionals but not just any professionals. AOE 4x4 Industries in Laguna Hills, California, was our go-to shop for this project. AOE 4x4 owner Alex Carvallo, and his team have a vast amount of experience modifying vehicles of all makes and models for extreme off-roading and exploration duties, but its specialty centers on the JK Wrangler. In fact, Alex’s daily driver is a fully built JK Unlimited that, when he’s not commuting with it through the streets of Orange County, California, is used to explore all over the USA’s unpaved outback for days on end. In addition to having the ability to cover anything from full-blown custom fabrication to more mundane installs and everything in between, AOE 4x4 even designs and builds its own line of products for 4x4s. We knew we could count on AOE 4x4 to conquer any challenges the 4-Link Extreme-Duty Long Arm threw its way. Read on for the install highlights and full story on Rubicon Express newest addition to its suspension lineup.
The Rubicon Express 4-Link Extreme-Duty Long Arm includes most of the components you see here. We clicked boxes for the optional front and rear replacement driveshafts, Rubicon Express monotube shocks, and T-case front output shaft yoke. Not shown is the optional High Steer Kit, which we ordered after the installation had begun.
The AOE 4x4 crew wasted no time getting our JK on the rack and ripping off the factory suspension. The Rubicon Express suspension requires the factory control arm mounts to be cut off the frame, so there’s no going back to the factory design.
The Rubicon Express bolt-on rear control arm mounts position the control arms up higher in line with the bottom of the framerail, so the factory rear mounts were cut off as well. Notice the rear driveshaft flange. The replacement Rubicon Express driveshafts came with a flange adapter rather than replacement axle yokes or a T-case rear output shaft yoke. More on that later.
The bolt-on frame brackets are by no means easy to install. The trouble is the boxed, hydroformed frame that doesn’t allow easy access to the mounting nuts and washers, as you can see here on the rear bolt-on rear control arm mount. Yet one more reason why we were more inclined to trust this installation to the professionals at AOE 4x4.
With the front upper frame brackets bolted on, the replacement heavy-duty transmission crossmember/front lower control arm mount is installed and the control arms fit into place.
The Rubicon Express system uses unequal-length upper and lower control arms, but the system works. The AOE 4x4 techs adjusted the pinion angle for the double-cardan driveshafts by lengthening the lower mounts accordingly.
The 3.5-inch-lift coils allow more uptravel than the simple spacer kit and factory shocks with extensions that this vehicle used to run. Still, note the use of the supplied bumpstop spacers inside the coil to keep the 35s out of the flares.
The Rubicon Express High Steer Kit moves the steering angles back into factory specs. The kit includes a heavy-duty drag link made from solid stock, OE tie-rod ends, and a new track bar bracket that also relocates the steering stabilizer above the drag link.
The bolt-on track bar relocation bracket ties into multiple points on the frame for additional strength. With the High Steer Kit there’s no need for a dropped pitman arm, which can place additional stress on the already wear-prone JK steering box.
Getting the steering stabilizer up above trail hazards is just one of the nice perks from the High Steer kit.
The Rubicon Express monotube shocks are specifically valved to work with the system’s coils and arm length. Special bolt-on brackets move the lower shock mounting points outboard of the factory shock mount locations on the axlehousing. The Rubicon Express braided steel brake lines come standard with the suspension system.
With the front suspension installed, the T-case yoke was swapped out and the front driveshaft installed. Note the factory T-case skidplate being reinstalled on the Rubicon Express heavy-duty crossmember.
Carvallo reported the rear driveshaft installation was a real pain, because the rear driveshaft conversion flanges didn’t allow access to the driveshaft mounting bolts. Tightening the bolts had to be done with a maddeningly high amount of microscopically small turns of the bolt heads.
Like the front, the rear suspension includes extended antisway bar links. Note the wheel spacers, which won’t be needed anymore thanks to our new wheel selection.
The factory rear track bar is a very strong piece so a replacement isn’t needed. A bolt-on relocation bracket on the rear axle raises the track bar for the taller suspension. The rear four-link long-arm works with the factory exhaust.
Like the front, AOE 4x4 was able to dial in the pinion angle for the double-cardan driveshaft, but after the lift was installed, they sent the vehicle to a local alignment shop to have a four-wheel computer alignment done to make sure the vehicle tracks properly down the road.
The new lift was the perfect time to make a big upgrade in the wheel and tire department, so a set of satin black 17x8.5 Pro Comp Series 5034 wheels with a 4.25-inch backspacing (PN 5034-78573) was selected so the wheel spacers could be omitted. On these, AOE mounted a set of 35x12.50R17 Pro Comp Xtreme MT2 tires.
The Pro Comp Xtreme MT2 is an exceptional all-around tire that’s quiet on the road, but gives great bite in all terrains from mud to rock to sand. So far, the owner of this Wrangler is more than pleased with their performance.
Suspension Report
The owner of this vehicle uses his Wrangler for long desert driving over rough, washboarded, and unimproved terrain more than rock hopping. The constant hit of the bumpstops (especially in the rear) that he was so fed up with is greatly diminished with the new Rubicon Express system. The on-road drive is virtually identical to what he remembers the vehicle driving like stock, and to date, there hasn’t been one instance of the ESP or other stability systems going haywire. After several thousand miles, the bushings have stayed quiet and clunk-free, and there are no steering or driveshaft-related quirks to report. It just goes to show if you select a quality product like the Rubicon Express 4-Link Extreme-Duty Long Arm and have a professional installation by somebody like AOE 4x4 Industries, you’ll wind up with far fewer compromises in the long run.
