You may be familiar with Black Diamond's Xtreme Coilover Conversion kit for YJs. Originally developed by Warn back in the late 1990s, the suspension fell into the hands of Black Diamond, which later became Superlift when the company acquired Black Diamond. The kit delivered one heck of a slinky trail suspension to the CJ and YJ, but that was the rub. It was primarily a trail suspension. While the four-wheel coilovers made for huge RTI numbers, they also contributed to some rather scary on-road handling characteristics and lots of body lean.
Enter Superlift's newly redesigned X2 suspension for CJs, YJs, and TJs. With the new X2 system, Superlift sought to deliver the trail articulation and performance of the old coilover conversion kit, but with stability, no noise, and civilized on-road manners. During the '06 Moab Easter Jeep Safari, we got behind the wheel of the Superlift X2-equipped YJ to see if the company hit the mark.
The X2 Suspension
Where the old kit used a complicated bellypan, clunky control arms, and coilovers at all four corners, the new 7-inch lift X2 system is a totally new entity.
For starters, the rear employs a nine-leaf spring pack in a spring-over configuration. The packs have triple military wrap leafs and feature 1/4-inch shackles, extra-long axle pads, and other tricks for decreased axlewrap. Superlift offers a traction bar called the Torque Fork for extreme-duty applications running big power or 37-inch or larger tires.
The front suspension uses the company's Rockrunner swivel-link radius arms. The arms attach to a two-piece skidpan that allows drivetrain access without removing the suspension. The 2-inch, .188-wall arms are designed to clear trail obstacles and use a swiveling link at the crossmember mounts to prevent binding. All mounting points use steel-encased rubber bushings for noise-free operation. The upper radius arm links are adjustable for pinion angle and caster adjustment. The front arms bolt to a stock TJ or XJ axlehousing, so upgrading to an XJ high-pinion Dana 30 would be easy. Weld-on brackets are available if you're reusing the stock CJ or YJ Dana 30 or upgrading to a different axle.
The front coilover mounts are bolt on, as is the rest of the kit (minus the front axle brackets). Some other odds and ends include Superlift's Kevlar brake lines, a dropped pitman arm, and trac bar drop bracket for proper steering.
To be honest, at first blush we were a little nervous about taking the Superlift Wrangler out. With a 7-inch lift and 37-inch tires, the sucker is tall, and no magazine editor wants to make the "I just rolled your company vehicle" phone call.
However, those fears were put to rest once behind the wheel. While the steering did have a slight vagueness to it (which we later discovered was due to the hubs being locked and the front locker) the rig was incredibly stable on the road. Even with the front sway bar disconnected, there was no wander, excess sway, or scary cornering.
After hitting the dirt, we were even more impressed with the Jeep's stability at angles and when climbing. On the flats and through bumps, there was a fair amount of head toss that we attribute to the shock valving, but when it came time to drop the T-case in Low and start crawling, everything smoothed out.
In the rocks, the suspension proved to be much more flexible than other radius arm designs we've driven. At full flex there was no binding of the bushings, thanks to the front arms' swivel links. In the rear, the thick spring packs proved very flexible, and there was no binding of the Torque Fork. Again, we credit Superlift's swivel-link design. The body stayed very level as the suspension dropped and tucked with the terrain.
On sidehills you can look down and realize how far above the ground you really are in this Jeep, but the seat won't travel up your rear end. There isn't that spooky feeling of imminent rollover you may experience with some other tall lifts. We credit the stability to Superlift's use of rear leaf springs.
All in all, we enjoyed our time behind the wheel of the X2-equipped Jeep. While the 7-inch suspension is a bit tall for our tastes, the company is said to be working on a shorter version that should fit the bill for those looking to run smaller tires or who are more comfortable cutting some sheetmetal.
Quiet, clunk-free ride. Great stability at angles, climbing, and crawling. Civilized manners.
Too tall for our tastes. Shock valving on stiff side. Steering feel not as crisp as we'd like.
You can run the most extreme trails one day, then toss the keys to a novice the next to pick up the kids at school.