Suspension Lift Kit Knowhow – Part 1
by Jim Allen
Suspension, along with tires and wheels, are most often the first 4x4 modification, forming the core around which everything else is built. A good combination of parts results in more enjoyment of your four-by. If you’re shopping for a suspension kit to go with a particular set of tires and wheels, here are some general tips for getting the most out of your choice whether you have leaf springs, coils, or an independent suspension.
Is your truck dedicated to the trail or is it a daily driver? The owner of a rig built only for the trail has fewer compromises to make and can be built more gnarly without worrying about bad manners or safety on the street. A daily driver needs to maintain a solid minimum of braking and avoidance maneuvering capability.
Tires and Wheels First, Please
Start with the choice of tires and build around that. Manufacturers of suspension lift kits will usually have a recommended lift height to fit the most popular tires and wheels. Start there, but don’t buy more lift than you need for a particular tire. That way, you keep the center of gravity low and that’s an asset both on the trail and on the street. Remember that advertised lift heights don’t always translate from one lift kit manufacturer to another, so look at each company's tire “fits or hits” chart. Wheel dimensions are another important element in the lift/tire size equation, so note anything the manufacturer mentions on wheel offset and width.
More Lift = More Bucks
The more lift installed, the more complications await you. That’s less true with leaf springs than coils or independent, but it’s universal that complications equal more cost (some not always directly associated with the lift). Tires and wheels would be included, as well as driveshafts, u-joints, and other parts. You can buy minimalist suspension lift kits that eliminate all but the most necessary corrective devices, but many find that turns into a case of false economy and later regret that choice. It’s often a better deal to buy the premium kit than to upgrade later. Another common-sense approach is to go with less lift and that costs less across the board. Every lift level has a threshold point where the cost goes way up. You can spot that point easily once you start shopping.
The Shocking Truth
Big tires dictate a change of shocks, whether you install a suspension lift kit or not. Aftermarket shocks can be hit or miss in the ride quality department for a particular lifted application for many reasons. There are so many tuning variables that it’s hard to produce the exactly correct shock for every combination of spring rate, tire size, and vehicle weight. Two things can increase your odds:
- 1. Use the shocks recommended for a particular kit.
- 2. Go with adjustable shocks.
In the first case, the quality of the match will depend on how well the engineers did their jobs. Bear in mind that few aftermarket companies can match the ride tuning that goes into a stock vehicle, but they have a better chance than you do of walking up and pulling an appropriate shock off the shelf. Adjustable shocks allow the driver the opportunity to fine tune the shock valves according to many individual factors.
A very common question concerns multiple shocks. Are they necessary? If you have really big tires and one shock cannot adequately dampen – maybe yes. If you are a desert racer wannabe and are cooking single shocks with heat – maybe yes. Keep in mind that modern remote reservoir shocks are so good that they can often handle what it once took two shocks to do, so for most four-wheelers a single good shock of the right size is more than enough. If dual shocks are needed, they should be valved to operate in pairs. Two shocks valved to operate as singles will produce a harsh ride.
Stay tuned for part 2 of our series on suspension lift kits where we'll delve a little deeper into leaf springs.