![Lifted 2001 GMC Sierra](https://upload.wikimedia.org/wikipedia/commons/b/b8/Lifted_2001_GMC_Sierra.jpg)
A suspension lift is a modification to a vehicle to raise the
ride height
Ride height or ground clearance is the amount of space between the base of an automobile tire and the lowest point of the automobile (typically the axle); or, more properly, to the shortest distance between a flat, level surface, and the lowest p ...
. It is done for the purpose of improving the
off road performance of
SUV
A sport utility vehicle (SUV) is a car classification that combines elements of road-going passenger cars with features from off-road vehicles, such as raised ground clearance and four-wheel drive.
There is no commonly agreed-upon definiti ...
s or
trucks
A truck or lorry is a motor vehicle designed to transport cargo, carry specialized payloads, or perform other utilitarian work. Trucks vary greatly in size, power, and configuration, but the vast majority feature body-on-frame construction ...
and other
off-road vehicle
An off-road vehicle, sometimes referred to as an overland or adventure vehicle, is considered to be any type of vehicle which is capable of driving on and off paved or gravel surface. It is generally characterized by having large tires with dee ...
s, or for cosmetic purposes. Suspension lifts can enable steeper approach, departure, and breakover angles, higher ground clearance, and helps accommodate larger wheels and tires. Due to the raised
center of gravity
In physics, the center of mass of a distribution of mass in space (sometimes referred to as the balance point) is the unique point where the weight function, weighted relative position (vector), position of the distributed mass sums to zero. Thi ...
, maximum safe operating angles can be reduced and roadholding is often significantly impaired. Suspension lifts are also found on a number of high performance sports cars, in which a very low ground clearance is used to improve handling, using an aerodynamic effect known as downforce; examples include the Ferrari 488, Lamborghini Huracan, McLaren 720S, and the second generation Ford GT. Such vehicles activate the suspension lift while traversing road bumps and ramps to avoid damaging the front underbody of the vehicle when driving on public roads; the suspension lift is deactivated on race tracks and level roads.
A lift kit is an
aftermarket product package with the parts needed to lift a specific model of vehicle, typically with instructions and customer support. Some kits may have only critical or difficult to obtain parts, needing generic or off the shelf hardware and parts to complete the lift. Some lifts need only a few parts, like lift blocks, the spacers placed between the axles and leaf springs, and coil spring/strut spacers and extended shocks, and special driveshafts, axles, and more. More extensive lifts require many new suspension, steering, and drivetrain parts, such as replacement
control arm
In automotive suspension, a control arm, also known as an A-arm, is a hinged suspension link between the chassis and the suspension upright or hub that carries the wheel. In simple terms, it governs a wheel's vertical travel, allowing it to mo ...
s,
trailing arm
A (semi) trailing-arm suspension, sometimes referred to as (semi) trailing-link is a vehicle axle or wheel suspension design in which one or more horizontal arms (or "links"), perpendicular to and forward of the axle, are connecting the axle or ...
s, custom four-link systems, and
drive shaft
A drive shaft, driveshaft, driving shaft, tailshaft (Australian English), propeller shaft (prop shaft), or Cardan shaft (after Girolamo Cardano) is a component for transmitting mechanical power (physics), power and torque and rotation, usually ...
s. These changes may be necessary because raising the vehicle's ride height can impact drive shaft length, steering geometry, and brake lines. Legality is often an issue when installing suspension lifts, as many jurisdictions have varying laws on vehicle ride height and placement of lights and bumpers.
Leaf spring lift
![Wdog Scrambler (cropped)](https://upload.wikimedia.org/wikipedia/commons/3/32/Wdog_Scrambler_%28cropped%29.jpg)
Many trucks are supported by
leaf spring
A leaf spring is a simple form of spring commonly used for the suspension in wheeled vehicles. Originally called a ''laminated'' or ''carriage spring'', and sometimes referred to as a semi-elliptical spring, elliptical spring, or cart spring, it ...
suspensions. Leaf springs offer exceptional
articulation, a large payload and can take a substantial amount of abuse. With the correct methods they can be modified to help a vehicle carry more weight, have better articulation or to fit large oversized tires. Some vehicles may be equipped with front and rear leaf springs or just rear leaf springs with independent front suspension.
Some methods of lifting are good for the rear, but not for the front, such as lifting blocks. Lifting the rear with blocks is a common way to achieve the desired height. This is done by installing a block, of the desired height of lift, in between the leaf spring and leaf spring perch and installing longer
U-bolt
A U-bolt is a bolt in the shape of the letter U with screw threads on both ends.
U-bolts have primarily been used to support pipework
Within industry, piping is a system of pipes used to convey fluids (liquids and gases) from one location ...
s. It is a bad method for the front primarily because of safety issues while braking. When braking, the front wheels create the majority of the braking force. The block moves this lateral force, caused by braking, higher above the axle than it did in the stock form. This can cause the block to become displaced from its location and result in total loss of control.
A more accepted way to build up the leaf springs is by using an add-a-leaf. This is done by inserting an extra leaf into the vehicle's leaf pack. Using the add-a-leaf will increase the height, but sometimes makes the suspension ride rough because of the added spring rate.
[http://www.jedi.com/obiwan/jeep/addaleaf.html] With an adequate budget, the best way to lift with leaf springs is to buy a new set with the lift built in. An add-a-leaf depends on the integrity of the old springs. They may be a bit worn out, so when the lift is installed, the proposed 2 inch leaves may only have lifted the truck 1.5 inches. The new leaf spring pack will not be fatigued and will give the true lift desired. These packs can be bought at various increments of lift and can be combined with lifting shackles to give the proper setup.
References
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Vehicle modifications