Air Suspension Terminology

Air bag / air spring 

An air spring is a rubber and fabric bladder that holds air pressure to support a load and isolate passengers from the shock of motion caused by road irregularities. Air bags replace the coil springs, not supplement them as is often thought.

Aired out

The look that everyone loves…zero air pressure in the springs and maximum drop.

Bellows air spring 

A type of air spring where the flexible member shape is a bellow (air chamber with flexible sides). These springs may have a number of bellows stacked on top of each other. For example, a double bellows spring as used in most Performance kits looks like two doughnuts stacked on top of one another. The more bellows, the longer the available stroke is of the spring. The greater the diameter of the bellows, the more load it can handle.


The angle of the front or rear wheels relative to the ground when viewed from the front of the vehicle. This angle refers to the inward lean of the tire. Zero camber would be perpendicular to the ground.

Camber plate

A style of upper mount for a strut suspension that provides for precise adjustment of camber angle of the wheels.

 Check valve

This is a one-way flow, mechanical valve attached to the output of the compressor that keeps the air stored in the tank from working its way back through the compressor causing a leak. They are typically connected to the compressor leader line.

 Compression damping

Force created by the damper to control the rate of upward movement of the suspension/downward movement of the body.


Refers to the forces created by the shocks/struts that control the oscillations of the body and suspension. Without proper damping, the vehicle would bounce uncontrollably down the road, or, if excessive, would make the ride stiff and uncomfortable. On the handling side, damping controls the rate of weight transfer across the chassis during transient maneuvers as well as tire loading, and thus, road holding.

 Double adjustable

A shock or strut that has independent rebound and compression adjustment provisions. 


Electronic Control Unit. Most often an ECU has some kind of intelligence and decision making power in a system.

 Handling balance

A description of vehicle behavior during limit handling (cornering) situations. A car with balance described as Understeer will have a tendency for the front to lose grip before the rear end and push towards the outside of the corner. Oversteer balance is the opposite of understeer. The rear of the vehicle will lose grip first which creates a potential spin situation if the driver does not properly react. A Neutral balance is the equivalent of handling nirvana and means both ends of the car stay connected with each other allowing the driver to make the least corrections and produce the fastest cornering speed.

 Leader line (hose)

The leader hose provides a flexible and durable connection from the air spring to the chassis mounted air lines. Ours are high strength rubber with a stainless steel outer layer for abrasion protection and long life.


In its simplest definition, a device that distributes air from a storage source to individual air springs. In the case of our V2 manifold, it also includes integrated valves, fittings, pressure sensors and ECU.

 Monotube Shock/strut

This type of damper gets its name from the single wall pressure tube where the piston and the oil do their thing to create damping force. Since the exterior wall of the damper body is in direct contact with the internal oil, these dampers stay cooler and more effective when pushed hard on track or rough road. Another feature to this design is lighter component weight when compared to other styles, thus reducing the unsprung mass of the suspension. These two benefits are why monotubes can be found on the vast majority of racecars as well as all of our Performance Series kits.


Another acronym that stands for National Pipe Thread. This is a universal thread standard for plumbing fittings and is the most common style found on aftermarket air systems.


This is an acronym for Push To Connect. Our air systems use this style of fitting to make installation and maintenance as easy and trouble free as possible. Simply inserting the plastic air line into the fitting and pulling on it to ensure a proper grip is all that is required to make a connection. Disconnecting a line is as easy as pushing on the plastic release ring and pulling the line out of the fitting. Even a caveman could do it.

 Rebound damping

Force created by the damper to control the rate of recoil of the spring/body/suspension as it extends to a greater length.

 Ride height

The height of the chassis relative to the ground when driving.

 Roll plate

A round metal device positioned between the bottom or top of a bellows style air spring and it’s mounting surface in order to stabilize the air spring.

 Shock dyno

A device used to measure and record the damping forces created by a shock/strut. Used in the development of dampers to determine a valving that will provide optimum performance. Yes, we have one. Yes, its cool.

 Sleeve style air spring

An air spring that has the flexible member in the shape of a cylinder. It typically uses a shaped piston on one end that creates a variable spring rate as the piston enters the sleeve. The larger the diameter of the sleeve, the greater load it can carry.

 Solenoid valve

In the our world, a solenoid valve is a simple 12volt DC actuated mechanical valve that opens and closes with a remote switch to allow air in-to or out-of an air spring. You want ‘em, we got ‘em!

 Spherical (ball) bearing

A bearing used in our camber plates and top mounts that permits easy rotation and articulation of the damper shaft while eliminating any vertical deflection. This bearing increases the effectiveness of the dampers and is used in high performance applications.

 Spring rate

The force required to deflect a spring a certain distance. Can be thought of as the stiffness of a spring. A higher spring rate requires more force to compress than a lower spring rate. The most common spring rate designations are lb/in or in metric, N/mm. The spring rate of an air spring is controlled by the design of the spring and the air pressure held in the spring. All things being equal, an air spring holding a higher air pressure would have a higher spring rate than the same air spring holding a lower pressure.


If we stick to suspension terminology instead of human anatomy, stroke refers to the total amount of travel your suspension has from full up to full down. This can be discussed in terms of the wheel travel or stroke of the dampers.

 Tapered sleeve air spring

Same as Sleeve style except the flexible member has a larger diameter at the top than the bottom, thus creating a taper.

 Twin-tube Shock/strut

As the name suggests, this damper style uses two tubes, one inside of the other. The working oil flows in and out of the inner pressure tube as the damper strokes through a “foot valve” on the bottom of the tube and an orifice at the top. Often times the nitrogen gas charge is emulsified (fancy word for “mixed up with”) the oil or contained in a plastic bag that is inserted into the damper when assembled. Advantages to this design include shorter overall damper lengths and reduced impact harshness as compared to monotubes, as well as reduced cost. The SLAM Series kits use twin tube construction.