Jeep Superlift Suspension Long Arm Kit - Long Armed & Long LeggedPosted in How To: Suspension Brakes on October 1, 2009 Comment (0)
A link-arm suspension's performance is limited by arm length. The longer the arms, the less their operating angles change as the suspension cycles, so you get less wheelbase change and bushing movement/wear/bind during articulation. Longer arms also reduce caster change. The long and short of all this is that a properly designed long-arm suspension noticeably improves both on- and off-road driveability.
Superlift's TJ/LJ (Unlimited) system wasn't the first long-arm kit on the market. The company dissected others' approaches, initially testing a three-link front design. Articulation was somewhat impressive, but side loads on the link arms ate bushings. Figuring that the average enthusiast wouldn't want to service his arms after every trail or two, Superlift scrapped the three-link and returned to the OE-style four-link concept.
To further improve articulation, Superlift uses its Rockrunner threaded-tubing setup for all eight arms. Since the arm swivels on itself, it won't bind. This system also uses OE-style steel-encased rubber and urethane bushings in the link-arm eyes. This combination is essentially noise-free, adept at damping vibration and shock loads, and economical to replace. The opposite is true of most Heim-type bushings. For strength, the Rockrunner arms are made from 0.188-inch-wall DOM tubing. They're contoured to allow full steering and maximum ground clearance while retaining proper geometry during cycling.
A two-piece skidpan assembly allows you to drop the 1/4-inch-thick primary pan to access the driveshafts, tranny, and transfer case, which remains supported by the 3/16-inch-thick inner pan. Superlift also offers a choice of progressive-rate springs: softer for softtops and slightly stiffer for hardtopped TJs/LJs.
Base Superide shocks are standard twin-tube hydraulic models. Upgraded SS monotube gas-charged shocks are sourced from Bilstein, and the SSR models add remote reservoirs. Superlift also offers a premium gas-charged remote-reservoir coilover conversion engineered to control lifting forces off-road. It uses a single progressive-rate spring to avoid the noise that typically comes with dual-spring coilovers. The coilover conversion isn't inexpensive, but it offers front ride-height adjustability.
The 6-inch kit also requires a fixed-rear-yoke transfer case-either a Rubicon or a slip yoke eliminator (SYE)-converted NP231-and a CV-style rear driveshaft. The 4-inch kit is case-by-case for an SYE on TJs, but the stock NP231 is generally OK on the longer-wheelbase Unlimiteds.
Installation & Impressions
Long-arm systems require many brackets, so installation time is significantly longer than lifts that retain the OE arm mounts. Many holes must be drilled through the frame, and Superlift includes anticrush sleeves for each. A transfer-punch kit and stepped drill bits save time. Above and beyond the parts needed for any SYE NP231 conversion, you will need an extended-length CV-style rear driveshaft, and exhaust modification is required to clear the skidpan and rear arms. Professional alignment is recommended following the installation, primarily to set caster.
Superlift also recommends professional kit installation since some cutting is required. However, the instruction sheet is detailed enough that the home mechanic who can competently torch or cut off OE frame welds should be able to handle the job. Estimated pro shop time is 10-12 hours, and Superlift rates the degree of difficulty a 5 on a scale of 1 to 5 due to bracket trimming and the number of holes that must be drilled through the frame. Jay Parodi of Tri-County Gear in Pomona, California, and an assistant tackled the job in a long day. The major steps are shown here.
Superlift's ballpark tire sizes are 33x 12.50s for the 4-inch kit and 35x12.50s for the 6-inch. However, the LJ shown here runs 37s with the Superlift 4-inch long-arm kit thanks to a Gen-Right Hi-Fender kit.
Overall, the Superlift long-arm kit provides a daily-drivable road ride with much-improved off-road articulation.