Project Silver Bullet Part 2
Of all the new products we spotted in Moab at the 2011 Easter Jeep Safari, one of the coolest was the new CRC Link from Full Traction. The bolt-on kit replaces the factory rear track bar arrangement on any ’07-and-later Jeep JK, and changes the way the rearend is located laterally. Mechanically speaking, the setup utilizes a variation of the roughly 200-year-old Watt’s linkage design originally developed for steam engines. Throughout the years, automotive engineers have adopted the technology to improve the handling of road racing vehicles. Full Traction is the first aftermarket suspension company to apply this technology to an off-pavement 4x4 application.
With the CRC Link setup installed, the axle moves up and down on one vertical plane, instead of in an arc relative to the chassis—a major disadvantage with track bars. This change in suspension motion is a good thing for several reasons: First, by eliminating all of the side-to-side movement of the rear axle, you gain stability during hard cornering. At first, this may not seem very important to you, but trust us, anytime you add stability to a suspension setup, you gain peace of mind during those curvy and sometimes treacherous mountain roads—you know, the ones that lead to most trailheads. Second, when the rear axle travels straight up and down, there is less transfer of sprung vehicle mass (weight above the springs). This lack of weight transfer helps to keep the rear tires in contact with the terrain, aiding traction. It has a constant roll center effect like that of a triangulated three-link arrangement, except you don’t get any any rear steer during articulation.
Aside from having a positive effect on the roll center of the vehicle, the CRC Link also fortifies the factory Dana 44 rear axlehousing, bracing it from the top and sides of the cast-iron centersection much like an axle truss does. Additionally, the arrangement splits the relative force of locating the axle laterally between each framerail, reducing stress and eliminating the issue of broken factory upper track bar mounts.
In Moab, we spent hours chatting with the owner of Full Traction, Steve Kramer, about how the CRC Link was developed. As he put it, “It’s not rocket science—the idea is over a century old, but it works. We simply re-oriented the pivot assembly to make it work within the confines of the JK chassis, and in doing so eliminated the stock track bar brackets.” We knew Kramer was on to something, so we secured first rights to review the product in prototype form. Some minor changes may have occurred by the time you read this, but we’re assured that function-wise, the production version should be identical to what you see here.
To evaluate the effectiveness of the CRC Link, we drove our JK through a variety of landscapes. First, we wanted to see if any additional noises could be found, so we drove the Jeep from Full Traction’s Bakersfield, California, facility to Los Angeles to test the setup in stop-and-go traffic. During this portion of the test, we couldn’t even tell that anything had been changed. Next, we took our chances on California’s scenic Highway 1 from Santa Monica all the way up to the Monterey Bay. Along the way, we stopped in at Pismo State Beach to run the rig through a ¼-mile section of whoops. After a few high-speed passes, we felt confident that the system added no additional noise to the rig’s suspension system. However, what we did notice in the whoops was that the rear axle moved up and down without any kind of lateral motion. This vastly improved the rig’s stability as the axle cycled rapidly through the whoops. It also allowed the jounces to land more squarely on the bumpstop extensions. After a few hard bottom-out events, we were convinced that the arrangement was not going to contribute any new noises, so we turned back to our on-road testing. California’s Big Sur coastline offered an excellent venue for us to feel the kit’s positive handling effects. During hard cornering (by “hard” we mean that threshold right before the tires begin to squeal), we found the handling of the Jeep to be much tighter than before. Gone was any significant body roll on hard left-hand turns and overall, the rear axle felt more planted. We suspect that the lack of track bar bushings might have contributed to the tighter feel. We punished the setup for nearly an hour non-stop, twisting and turning with the majestic cliff lines of Highway 1. Once we reached Seaside, California, we stopped to check the system’s various fasteners. (You never know what might come loose on a prototype arrangement.) Everything was tight, and nothing seemed out of place. We have yet to do any serious rockcrawling with the CRC Link installed, but feel confident about the strength of the system. We plan to provide an update on the system in the Silver Bullet’s next build segment.
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