Do brush your teeth at night. Don't pee on an electrical socket. Do tip your waiter.
Don't pick up chicks with Adam's apples. Seems simple enough, right? But when it comes to modifying or building your coil suspension, the rules aren't as cut-and-dry. Unlike leaf springs, where you only have to worry about a couple of things like shackle inversion and lift height, coils offer a whole slew of intricacies. Technically, you can bypass a lot of the suggestions that we'll run down for you, but you could be left with compromised performance, annoying quirks, and a potentially unsafe situation. Furthermore, getting a coil suspension, whether standard coils or coil-on-shock systems (coilovers), set up to offer good off-road performance without negative on-road characteristics requires some forethought. Here are but a few things to consider as you modify your Jeep with the round-variety of springs.
Do: Put a little extra money into higher-end shocks if you're running a coil suspension.
Don't: Just run a basic cellular gas shock and wonder why your fillings get knocked out off-road at high speed.
Unlike leaf springs, which increase rate progressively as the spring compresses, coil springs offer a linear spring rate which stays the same until the spring fully compresses. The exception is multi-rate springs, which have different spring rates wound into the spring itself. Since most coil springs don't get harsher on compression, they can offer a smoother ride compared with leaf springs. But they can also require more advanced shock valving if hard, fast use or jumping is in the cards. A shock with progressive-rate valving that firms up at the top of the stroke can help soften the harsh impact as the axle mashes the bumpstops and will make for a more-controlled ride.
Do: Go ahead and run an inexpensive spacer lift as long as you address other components that may need modification.
Don't: Stack multiple spacer kits to gain more lift.
Running coil spacers to gain a little extra lift is a completely acceptable practice. Although many suspension manufacturers sell spacers by themselves, keep in mind that adding spring spacers taller than 1.5 inches in height will usually require modifications like longer shocks, dropped bumpstops, and possibly minor steering or brake line corrections. However, when used properly, coil spacers are a great way to gain a little height for a little money.
Do: Cycle your suspension and limit uptravel before coil bind occurs.
Don't: Turn up your radio and ignore the sounds of spring carnage.
Also unlike leaf springs, coil springs will compress under a vehicle's weight and then keep on trying to compress after they've reached their minimum height. This is known as coil bind and can occur unless the suspension is articulated and the bumpstops lowered accordingly. In addition to adding racket and possible damage to brake, Unitbody, frame, or steering components, coil bind is a quick way to destroy a nice pair of springs.
Do: Run swaybars on-and off-road with quad-coil suspensions.
Don't: Assume massive flex means massive performance.
When you run coil springs, sway bars are your friend. This is especially true when you're got both front and rear coil suspensions. We know a lot of enthusiasts like swaybar disconnect systems for jaw-dropping flex, but running no swaybars on a quad-coil suspension is a recipe for instability and a possible rollover. We always prefer running at least a front torsional swaybar like the Currie AntiRock. If fast street or off-road driving is in the cards, adding a rear torsional swaybar will add a great deal of stability, help keep all four tires planted during hard cornering, and won't impede flex to any great degree.
Do: Consider an adjustable upper coil mount to dial in your ride height and level your Jeep before you buy coils for your desired ride height.
Don't: Decide to add them later, get bummed at how tall your Jeep sits, and then have to buy new coils.
A nice upgrade to simple coil spring spacers, the Adjustable Coil Spacers (ACOS) system from JKS can be had with or without built-in hydraulic bumpstops and allows you to dial in your ride height and level your Jeep side-to-side by turning the spanners through their 2.25 inches (front application) or 1.37 inches (rear application) of travel adjustability. One caveat to the ACOS and most adjustable coil bucket mount systems is they add about 1.5 inches of height to the suspension. You also want to employ a lower spring retainer, whether factory or aftermarket, to keep the bottom of the spring from rotating out of its bucket mount and think about adding limiting straps to prevent the coil from unseating in the upper bucket.