Leaf, Link, Coil, Or Coilovers
Everybody has a favorite. Some guys are content to slap on a dime-store lift and call it a day, while others wanna continually tweak and fabricate until perfection is reached. Still, other guys just throw booty-fab and booger welds at a frame until the axles can flex clear to the other side of the vehicle, spitting coils and snapping brake lines in the process.
Which is right for you? Well, that largely depends on your design and fabrication abilities. Although we're discussing certain pros and cons of suspension types, keep in mind that the simplest well-designed stock suspension will work much better than a complicated, yet poorly designed crazy-fabbed suspension.
John Cappa Says
A well-thought-out four-link suspension like what can be found on the front and rear of TJs and Grand Cherokees and the front of XJs and MJs is perhaps the best-performing off-road suspension your Jeep can have. However, a poorly-engineered home-built four-link with little consideration for spring rate, anti-squat or roll-center will perform worse than any factory leaf spring suspension. So if you have no idea what these terms mean, you have no business building your own four-link. Your efforts will likely result in an overly-flexy RTI ramp champ that's worthless in the real world and scary out on the trail.
A custom triangulated three-link suspension is a great way to simplify a rear suspension and eliminate the sometimes problematic track bar. Although, a four-link rear suspension with a track bar will typically handle better on- and off-road. The track bar locates the rear axle better. A triangulated three-link is not a good idea up front. Your turning radius will be adversely affected and there will be noticeable bumpsteer unless the steering has been completely redesigned to cycle and move in sync with the suspension. You are better off with a three- or four-link with a track bar if you plan to use the conventional steering box and crossover steering commonly found on most Jeeps.
When a link-style suspension is utilized there are a number of different springs that can be used to support the Jeep and provide suspension travel. The simplest and cheapest is a stand alone coil much like what you would find in the front or rear of a '97-present Wrangler. The coils are located by brackets that are welded onto the frame and axles. Spring rate and lift height are limited by the coils that are available for your brackets. Coilovers are a little simpler to mount, but they offer the advantage of a shock and coil in a nice compact unit. They are also much more expensive and infinitely more adjustable in terms of spring rate and valving, giving your Jeep nearly unlimited possibilities based on what it weighs and your driving style. Air or nitrogen shock springs are not a good option for a Jeep that sees real world trail use. They can heat up during faster trail sections causing the spring rate to increase. This will cause your suspension to perform less than ideal in a given situation. An often untapped spring for a link style suspension is the leaf spring. By combining a leaf spring hung on two shackles with a properly designed four-link you end up with an extremely predictable and stable suspension that provides great performance. It is, however pretty complex and can be significantly heavier and harder to install than a coil-over or stand-alone coil spring.