Installing Rock Krawler's Jeep ZJ 4.0 X Factor Short-Arm System
The Rock Krawler 4.0-inch X Factor short-arm suspension kit is available for '93-'98 Jeep Grand Cherokees. It is a bolt-on system that uses adjustable front control arms with upper high-misalignment Krawler joints and a triangulated four-link conversion rear. The system permits use of 31-inch tires. The control arms and track bar are made from solid stock material. The rear track bar is eliminated with the installation of this kit and removal of the factory rear upper control-arm axle mounts is required. We installed the kit on a well-worn '94 Jeep Grand Cherokee ZJ with the 5.2L V-8 and Dana 35 rear axle.
The rear triangulated four-link conversion includes a mounting cradle/axle truss that's made from 1/4-inch-thick laser-cut steel and secures using two U-bolts around the axletubes and also around the perimeter of the diff cover. A weld-in cradle/truss option is also available.
The triangulated four-link rear is designed to provide the proper antisquat geometry for increased climbing ability and also permits a great deal more downtravel for tackling difficult rutted or rocky obstacles. Highway ride is also well maintained, very closely mimicking the factory characteristics. We also ordered a set of Rock Krawler shocks and installed a set of extended stainless steel brake lines, which are included in the kit. Rock Krawler also recommends installation of an SYE kit and CV driveshaft or a transfer-case drop-down kit to maintain proper driveline geometry and eliminate any binding. For those who eventually want to run larger tires, the X Factor short-arm system is easily upgraded to Rock Krawler's long-arm system using new longer control arms and a new centered crossmember/skidplate.
Topping off the Rock Krawler system, we mounted a set of 31x10.50R15 Pro Comp Xterrains to a set of 15x8 Pro Comp Rock Crawler Xtreme steel wheels. The staggered, directionally grooved tread pattern is both unique and functional. The tires offer extra-thick two-ply sidewalls with opposed-angle steel belting across the tread that permits ample tire flex, particularly when aired down. The tires provide a good highway ride with exceptional capability off-road.
With the Rock Krawler X Factor system in place, the Grand Cherokee offered a much more comfortable highway ride than the aging '94 coil springs provided, but the true test came on the trail. Even though we only increased tire size slightly, the increased flex afforded through the X Factor kit was substantial, and increased off-road capability was the result. With more suspension downtravel, the Grand Cherokee was able to tackle more difficult obstacles since the rear wheels could better maintain traction. This was most noticeable in deep ruts where the ZJ was still able to climb out and continue forward motion without repeatedly backing up to rock the vehicle through. Steep hillclimbs are also much more easily accomplished thanks to the rear triangulated four-link conversion.
For installation of the Rock Krawler 4.0 X Factor system, we called on Mel Wade of Off Road Evolution in Fullerton, California. The crew at ORE is well versed in Jeep suspension systems and completed the install on our '94 Grand Cherokee in just a few hours.