April 23, 2018
Suspension systems consist of a wide range of parts that work together to provide optimum handling for your vehicle, whether in stock condition or with aftermarket additions. We've compiled a reference list of part names and their functions to make it easier to understand how each part is used. While not an exhaustive list of terms, this will get you started with some essential knowledge. We'll start off with some basic terms and then dig a little deeper into some more comprehensive terms. If you've got further questions, give our tech specialists a call at 877-216-5446. We're here for you.
Alignment: Often thought of in the context of wheels, this refers to the way that suspension components are adjusted so that wheels are angled correctly.
Body: The part of a vehicle that contains the cab, bed, and any other portion of the vehicle that carries passengers or cargo.
Body Lift: Raising a vehicle's body higher off the frame using blocks and spacers; ground clearance does not change.
Frame: On a body-on-frame vehicle, refers to the supporting structure that the body is mounted to.
Full Frame Body: Vehicles with a full frame have a body, or main cabin, are mounted to a separate frame, or chassis. They tend to be tougher than unibody frames and are often found in four-wheel and all-wheel drive vehicles.
Suspension: The components of a vehicle that maintain steering stability while ensuring a smooth ride over terrain.
Handling: The way in which a vehicle accelerates and brakes, as well as corners.
Level: Increasing front ride height by 1 to 3 inches with spacers or other suspension components.
Lift: Raising a truck or SUV higher off the ground, whether via body or suspension lift.
Suspension Lift: Increasing the height of a vehicle's suspension and, in some cases, its ground clearance, with front and rear components such as taller coil springs, spacers, add-a-leaf springs, and lift spindles.
Unibody: Vehicles with a unibody frame are designed for the main vehicle cabin to act as the frame. Not commonly seen on pickup trucks or SUVs.
Adjusting Sleeve: Tie rods have adjusting sleeves that allow the tie rod's length to be fine tuned.
Air Bag Suspension: Adjustable suspension components that are great for towing as they improve handling ability and ride comfort.
Ball Joints: The joint that connects the control arm at the wheel to the steering knuckle.
Bump Stop: Suspension component that compresses to absorb high impact, such as driving over a bump at speed. Often used to prevent damage to a vehicle's axles.
Coilover Springs: Also known as coil spring over shock, coil over springs consist of a shock absorber inside a spring. Usually assembled together, they absorb impact and provide damping.
Control Arms: Control arms connect a vehicle's suspension to the frame. Most truck drive-wheel configurations (four-wheel drive, rear-wheel drive, and all-wheel drive) have upper and lower control arms, while most front wheel drive configurations just have lower control arms. On solid axle vehicles with coil springs, control arms keep the axle located.
Upper Control Arms: This is the upper locating arm in an independent suspension. This is often replaced by a steel tubular or boxed arm in premium aftermarket lift kits.
Lower Control Arms: This is the lower locating arm in an independent suspension. This is often relocated with drop brackets in suspension lifts over 3 inches or so (at least in 4WD trucks) so that CV angles remain within specifications. These are not often replaced unless you're using a mid or long travel suspension.
Damper: See Shock Absorbers.
Differential: A vehicle's differential allows wheels to rotate, or travel, at different speeds, for example when turning.
Drag Link / Center Link: A drag link, also known as a center link, connects the left and right tie rods together.
Drive Shaft / Prop Shaft: The drive shaft connects to a vehicle's transmission and employs torque to rotate the wheels.
Leaf Springs: Curved stacks of metal strips that absorb impact. Usually found on the rear of modern pickup trucks.
Pitman Arm: This is the arm that connects the steering box to the drag link and keeps steering angles in check.
Relocation Brackets: Designed to work with lower controls arms, relocation brackets prevent wheel hop, or wheel shakiness.
Shackle: Shackles attach a leaf spring to the vehicle's frame.
Shock Absorbers: Suspension component that absorbs vibrations and bumps to ensure a smooth ride. Check out more information on how to choose shock absorbers.
Spacers: Spacers, also known as blocks, fit on existing suspension components to raise the vehicle from 1 to 3 inches. Usually applied to coil and leaf springs.
Spindle: Attaches the wheel to the steering system.
Springs: Suspension components that absorb impact.
Steering Knuckle: A steering component located at the wheel that holds the spindle. It is connected to suspension components.
Tie Rods / Tie Rod Ends: Tie rods connect the wheels to steering components. Because the tie rods connect to other components on either end (drag link on inner end, steering arm on outer end), they get a lot of use and therefore need to be well maintained.
Transfer Case: In vehicles with four-wheel-drive and all-wheel-drive, a transfer case transfers transmission power to the axles via drive shafts.
Uniball: Typically replaces ball joints in tubular or boxed replacement upper control arms. They are more robust and allow for more suspension travel, though they can be noisy, and have a shorter service life than ball joints.