Jeep Wrangler (TJ) Suspension & Lift Basics
The Jeep Wrangler (TJ) was a huge leap forward for Jeep's smallest SUV. Though it looked basically the same outside, save for the return to round headlights, the suspension underwent major changes.
Gone were the old leaf springs. In their place went a full coil suspension, similar in design to that of the Grand Cherokee. Immediately the benefits were seen - increase comfort onroad and off, better handling in both mediums and, for the jeeper wanting more than the factory offered, now existed the path to truly amazing suspension articulation and go-anywhere capability.
As with any suspension lift, these will basically put more space between the axles and the body of the Jeep. This will then allow you to fit larger tires - and this is where you get additional ground clearance.
The great part of lifting a TJ is the ride quality is retained and where leaf springs promise a ride-performance trade-off as lift increases, coils will allow you to increase the lift height without the tradeoffs in ride quality. This basically means your 6" lifted TJ can still pull duty as your daily driver without too many concerns.
Suspension only? Or body lift, too?
The body lift is included to ensure the larger tires can cycle through the full range of suspension movements without touching anything.
The nice thing is that lifting a Jeep Wrangler (TJ) is easily done in stages:
• A 1 inch body lift will allow you to easily clear a slightly larger tire than stock, very inexpensively
• A 2 inch suspension lift would allow another tire-size upgrade, and increase ground clearance as dollars allow
Combine this simple lifting strategy with aggressive fender trimming, and you could stuff 35" tires under that rig of yours - that would be good for almost 4 inches of extra clearance (over stock) under the axles - but you'd want to look at upgrading those axles if you're going with a tire over 33".
Other Lift Considerations
Running out and slapping on some pucks under your body tub might sound easy, but there is a bunch to consider before the wrenches start flying:
• Get replacement bolts ready - the old rusty ones will be tough to get out and you'll want new ones to install
• Make sure you use actual body lift components - some areas will not allow a Jeep equipped with hockey pucks as body mounts to pass inspections - don't laugh, it happenes every day
• Be ready to lengthen wires and control linkages as needed - going up 1 inch shouldn't pose a problem, any higher might. You'll need to fabricate longer shifter and t-case handles, and watch for any other items which need lengthening.
• DO NOT run a body lift any higher than 3 inches - even that's a bit much. All you are doing it raising the centre of gravity and rather than the lift blocks supporting the mass of the body (and you) vertially, the bolts now must carry the weight through the turns. Think of it - does it seem safe to have 6, 1/2" or so bolts holding roughly 2500 lbs worth of body tub and humans in place? Keep it to 1 inch if at all possible.
There are a bunch of suppliers who offer complete kits, and this truly is the best route to follow. Luckily, the kits generally include the major components which will need upgrading. That said, be ready for custom fabrication if you go higher than 3" of lift.
Don't forget, if you raise the suspension, you'll need to install longer trac bars to locate the axles and adjust or replace steering components to keep the angles of steering-related items within specs. A full, complete kit, will have everything you need. Be sure to double and triple check those trac-bars - there's two in TJ Wranglers - one for each axle. Their job is to located the axle under the Jeep - if you hear a clunking noise after the install, chances are the mounting or location bolts/nuts are loose. In general, these nuts/bolts cannot be tight enough. Re-check them periodically and after every two or three trail rides. As with any suspension changes, go get an alignment when you're done.