Bushings
Whereas most aftermarket control arms are attached to the vehicle with either polyurethane bushings or spherical rod ends, JKS chooses good old-fashioned rubber. This decision is considered controversial by those who prefer synthetic bushing materials for their more resilient qualities; however, JKS only uses the high-quality, vulcanized rubber bushings that are found on the original equipment suspension arms. These genuine OE parts are far superior to the lower-grade alternatives commonly sold as replacements.
The most obvious benefit of using rubber bushings is immediately noticeable inside the vehicle. Unlike denser materials, rubber bushings do an extremely effective job of isolating noise and vibration that would otherwise resonate into the vehicle cabin. Almost anyone who has replaced the factory suspension arms with aftermarket components can likely recall the immediate effect from the driver's seat.
Another important advantage of using rubber bushings involves their impact on the related mounting brackets. Although rarely mentioned, firm polyurethane bushings and rigid control arms can actually tear the factory mounting brackets away from the chassis or axle when exposed to severe conditions. On the other hand, high-quality rubber bushings are able to absorb damaging impacts and lateral forces instead of resisting them. Needless to say, a broken control arm bracket on the trail is not a situation you want to experience firsthand.
Materials and Finish
One can't help being immediately impressed when holding a JKS control arm in one's hand for the first time. While surprisingly simple in appearance on the outside, the unit's weight is the first suggestion that there is more than initially meets the eye. The heavy-gauge steel body is finished in rich black powdercoat, and the rotating 1.25-inch-diameter, solid steel rod has received a protective zinc plating. The rubber bushings at each end are easily identified as original equipment parts.
JKS informed us that it keeps a supply of new bushings on hand in the unlikely event of the originals wearing out, but the company assured us that this circumstance is extremely rare. JKS was also proud to announce that it has never had a control arm fail or wear out since it introduced the product more than six years ago. Now that we've had a firsthand look from the inside out, we believe 'em!
Extended-Length Control Arms
Many suspension manufacturers now offer control arms that are much longer than normal as a means of compensating for the increased operating angles. Although they can reduce the operating angles considerably, they no longer utilize the factory chassis mounts and some even require custom fabrication to install. Due to the additional factors involved, we won't go into greater detail on extended-length arms in this article; however, we will mention that you may find the benefits of extended-length control arms to be well worth the effort and expense if your Jeep is lifted or used to the extreme.