A suspension lift kit raises the suspension of the vehicle by replacing front and rear leaf springs and shocks. This can create greater suspension travel and articulation, it can allow for significantly taller tires improving clearance between axles and ground. Articulation should improve with a good suspension lift kit, but because the steering geometry is affected, some people choose to add steering stabilizers to reduce “bump steer”. An easy suspension lift on the rear of a vehicle is to add (or increase the height of the existing) suspension blocks on the rear, although adding significant blocks to the rear suspension may induce “axle tramp” (this is a vibration of the axle under acceleration), in addition to affecting driveline angles. DO NOT add suspension blocks on the front suspension.

A suspension lift kit is more expensive than a body lift, but produces better results in terms of height, handling and ground clearance. Suspension lift kits are usually 4-inch (10.16 cm) or 6-inch (15.24 cm)lift kits. There are lift kits as high as 18 inches (45.72 cm), but extreme lifts drastically compromise safe handling, look odd by most standards, and are not commonly installed except on showcase or hobbyists' cars.

If considering a lift kit over 4 inches, remember that the higher you raise the vehicle's center of gravity, the less stable it will become when making sharp turns at high speeds. The jerk of the wheel might not be a problem for stock suspension or even a 4-inch lift, but at 6 inches or higher, more caution must be used. The vehicle might also have a tendency to lean more in banked turns such as freeway interchanges and offramps, so it is important to refamiliarize yourself with the feel of the truck, SUV or jeep after installing a lift kit.

If your main objective in installing a lift kit is to get larger tires, your speedometer and odometer will both become inaccurate. You will also need to fit new gears to the differentials to account for the new tires' circumference. There is a good calculator here for working out what gear ratio you will need. http://www.ford-trucks.com/calculators/index.php/p-overall_gear_ratio/ . Just enter your stock tire size and stock gear ratio. This information is often included on the metal plate located in a door jam or by the engine. Sometimes it is encoded in the vehicle identification number (VIN). Re-gearing will also keep the mileage as close to stock as possible. If you are only going up one tire size, you may be able to get away without re-gearing.

Several different manufacturers make lift kits. Prices vary, depending on the model and type of lift kit. A very nice 4-inch suspension lift kit, for example, can be as little as a few hundred US dollars. However, add to this the cost of a set of four tall tires and re-gearing, and the entire modification can easily cost US$2,000 or more. New tires are not necessary, but stock tires will look conspicuously small in higher wheel wells.