What is a Convoluted Air Spring and how to identify or measure it

August 23, 2022

Latest company news about What is a Convoluted Air Spring and how to identify or measure it

The convoluted air spring consists of a rubber bladder with cords and compressed air enclosed in it. The inner layer of the airbag is made of airtight rubber, while the outer layer is made of oil-resistant rubber. The airbag is generally made into double bellows, but there are also single bellow or three or four bellows. The more the number of convolutions, the better the elasticity, but the sealing is poor. There is a steel waist ring between the sections to prevent the middle part from radial expansion and prevent the two sections from rubbing against each other. The upper and lower cover plates of the air bag seal the air bag.


Convoluted air springs are generally used for lifting axles and preserve the tires when the vehicle is empty. Aside from that, they are also utilized in industrial applications as pneumatic lift cylinders or suspension elements to absorb vibrations. These air springs are easy to mount and they last long.


Convoluted air spring is consist of the following components.

Air fitting: A tapped hole allowing for the spring to be fed from the air compressor

Nut/bolt/mount: The method for attaching the air spring to the component. Some air springs incorporate a bolt and air fitting combination device.

Bead plate: Crimped metal plate enclosing the spring and allowing attachment. This is typically forged steel, cast zinc alloy or cast aluminum.

Bellows: The physical, multi-layer material withholding the compressed gas. Usually made of neoprene or rubber.

Girdle: Only found in air springs of convoluted design, separating the bellows chambers.

Bumper: An optional layer of padding protecting the piston from damage if the air spring fails.


The air spring has two numbers, one is part number and the other is bellow number.


The easiest and fastest way to identify air springs is by the part number which normally located on the sticker on the top of the air bag.


If you don't know the part number, then you can measure it according to the following steps.

The first is to identify the bellows number, which is the first step in identifying any bag or air spring. The bellows are the rubber portion of the airbag, and this number will determine the ride height and weight capacity of that airbag. The bellows number is located on the rubber oval stamped into the rubber. All convoluted bags use will bead plates. It's the flat plates on the top and bottom of the bag. You need take note of any connection points or air fittings and measure the distance between them. It is also necessary to note the size of your air fitting as well as the diameter of the top plate. On the bottom plate, you'd take the same measurements, the diameter across the bottom plate, and the measurement between the screw or blind nut. Then a compressed height need to be measured. Remove any air from the bag and press it down by hand, measure the distance between the top and bottom plates, and compress. Also pay attention to whether the bag has an a bumper block/buffer. It's easy to determine if a bag has bumpers. The bag rocks when you compress it. On bags without bumpers, the plate will lie flat and you won't be able to shake it.