Air Suspension Terminology

Air Spring The rubber bladder assembly that replaces the metal coil, leaf, or torsion spring in a vehicle suspension system, often referred to as an Air Bag.

D.O.T. is short for Department of Transportation. Certain fittings, tanks, and lines are D.O.T. approved and meet higher quality standards and fail safe designs in order to comply.

F.B.S.S. is short for Front, Back & Side to Side. This is the same as saying individual control over each air spring. At AccuAir, we call these systems “4-way”.

P.T.C. is short for Push-to-Connect. P.T.C. fittings accept a special plastic airline that simply pushes into the fitting and seals with an O-ring located within the fitting. The fitting’s collet tightens on the airline automatically and increases its force as pressure increases. To disconnect the airline from the fitting, you must first push the collet and airline all the way IN, then keep holding the collet IN while you pull the airline OUT. Note: a 3/8” open-ended wrench is a handy way to hold the collet IN, while you pull on the airline OUT.

Ride Height is the height that you drive the vehicle at, (sometimes called driving height). This is the height where you will have the vehicle aligned.

Rubber Bellow is the rubber part of the air spring. The metal end caps are usually referred to as top and bottom “plates”.

Spring Rate describes the stiffness of a spring usually measured in lbs/in (pounds necessary to compress the spring by one inch). Almost all air springs have a progressive spring rate, which means that they get stiffer the more they are compressed.