Jeep Grand Cherokee ZJ Lift - Better than StockPosted in How To: Suspension Brakes on November 12, 2007 0) (
That old ZJ you've owned for years (or maybe just bought used) just doesn't ride and work the way it used to. The rear springs sag with the slightest bit of camping gear or a couple kids. The body leans in corners so much you think you'll lose the door handles at the next on-ramp. The control arms constantly squeak and thunk, not only at every expansion joint or speed bump, but also during quiet drives through the backcountry. So much for enjoying the serenity of nature.
Maybe it's time for some upgrades on the ol' hoss. Nothing extreme - you want to keep the great dual-purpose nature of your Grand Cherokee intact - but it could definitely use some more off-road capabilities. Then again, you could just replace everything with stock parts from a dealer, but you'll end up paying almost as much as an aftermarket lift kit (see The Cost of Freedom) - and you'll end up with nothing more than a stock Jeep. Well, we're Jp Magazine, the cure for the stock Jeep, and we're going to show you how to make a ZJ grand again.
Yes, you could buy the stock parts from Jeep, do a lot of work installing them, and end up with a perfectly stock riding (and performing) ZJ. Where's the fun in that? For just a couple more Ben Franklins you can get a Rubicon Express suspension kit with higher-quality, taller springs that provide more tire clearance (3.5- to 4.5-inch lifts), stronger control arms that allow more flex (either Super-Ride or Super-Flex), plus sway bar disconnects that give you even more articulation off-road. Oh, and if you decide you want the tops in trail performance later, Rubicon Express offers its 4.5-inch Extreme-Duty Long Arm system. We decided the 3.5-inch RE8003 Super-Flex kit best fits our dual-purpose usage for our Grand at this point, but here are some ballpark prices (at press time) compared to using stock Jeep pieces.Stock Jeep* $690Rubicon Express RE8005 (3.5-inch Super-Ride kit)** $700Rubicon Express RE8003 (3.5-inch Super-Flex kit)** $880Rubicon Express RE8000 (4.5-inch Super-Flex kit)** $1,463Rubicon Express RE8300 (4.5-inch Extreme-Duty Long Arm kit) $2,809 *Price includes new front and rear springs and all control arms with bushings only. Note that the front upper bushings at the axle will still need to be added with any upgrade because they are not part of the control arms.
Whenever you lift a Jeep (or any 4x4) using a suspension lift, the distance between the shock mount on the frame and the shock mount on the axle becomes farther apart. This means you must now replace the shock absorbers with longer units that do not restrict downward suspension movement. But be careful and don't go overboard on the length - a longer shock is longer both extended and compressed. The suspension must still be able to compress without bottoming out the shock and possibly damaging it. Either measure your vehicle at ride height and make sure your shock is in the middle of its travel, or use a shock specified by the suspension maker. The pros will leave the springs out and cycle the suspension while taking measurements at full compression and full droop. Sometimes bumpstops will need to be extended to limit some of the up-travel in order to save the shock. A set of Edelbrock's XTreme IAS shock absorbers (PN 63518 front, PN 64518 rear) fit the bill perfectly. These shocks stay within our Grand's dual-purpose nature yet don't skimp on the performance with 51/48-inch rods, 46mm pistons, and the Ricor Inertia Active System which shifts the damping from soft in the rough to firm on pavement. Plus, the zinc-plated finish looks great with the silver powdercoat on the Rubicon Express hardware.
For Grand Cherokees (and baby Cherokees, for that matter) with shorter lifts, there is one wheel and tire combination that simply rocks and is gaining popularity. Most Grands with only 3.5 inches of lift (XJs usually need an additional 1-2 inches of lift due to their smaller wheelwells) are stuck running 31- or maybe 32-inch tires, if you're lucky. The next step, a 33x12.50-15, will crunch your fenders unless you Sawzall them first. But there's another choice. The size you need to keep your fenders intact is the 33x10.50-15. Only a handful of tires in this size are available, and over half of those are made by BFGoodrich so choose the All-TerrainKO, Mud-TerrainKM, or Baja T/A.The other half of the secret is to use either a 7- or 8-inch-wide wheel with as close to 4.5-inch backspacing as possible. Again, these are difficult to find in a 15-inch diameter (16 inchers are easy but then you have to run stiffer D- or E-load rated tires). In fact, off the top of our head, we could only think of Alcoa's Classic (PN 458421 for 5-on-411/42 bolt pattern), so if anyone knows of others, be sure to let us know. (The five-spoke wheel shown in the photos is a discontinued, Alcoa-designed 15x7 called the LTS.) Note how, even though the tire is a 33 incher, the narrower section width tucks cleanly up into the rear wheelwells. Up front, the rear of the plastic bumper will need to be trimmed slightly to clear the tire during turns with the suspension compressed. With the Rubicon Express lift and Edelbrock shocks,