Air Suspension, No Springs Attached

Low when parked, sensible when driving. Air suspension gives you room to do both. The component names and control options can be a little confusing at first, so let’s clear the air.

Air suspension FAQ

What exactly is air suspension?

It’s suspension that uses air springs instead of conventional steel springs. The dampers still do their usual job, but the springing comes from compressed air inside flexible bellows. Add or release air using the controls, and you can adjust the car’s ride height along with the behaviour of the air springs.

What’s the difference between manual and automatic management?

With a basic manual system, you adjust the height yourself using buttons or paddle switches. You’ll soon learn which pressures give your car the height you want under a given load.

An automatic system adjusts to a saved pressure or height setting for you. Depending on the system, you can store several presets and switch between them without doing the button dance every time.

What about phone apps and remote controls?

Some systems offer a phone app or remote controller. These let you adjust the suspension and change settings conveniently, even from outside the car.

What’s the difference between axle and four-corner control?

An axle-based system, also known as a two-circuit system, adjusts the front and rear axles separately. A four-corner system gives each air spring its own control circuit. This allows more precise adjustment and, depending on the management system, better compensation for different loading conditions.

Do I need height sensors?

They’re particularly useful when the load changes. The pressure that gives you the right height when driving alone may leave the car sitting lower once your passengers climb aboard. Height sensors measure the suspension position, allowing a compatible system to adjust to the actual ride height.

Can I use air suspension in winter?

Yes, provided the system is suitable for winter use. Plenty of cars leave the factory on air suspension, as does a fair amount of the heavy machinery sharing the road with you.

The thing to stay on top of is moisture. Water has a well-established habit of freezing in cold weather. The system needs an effective water separator, and you need to remember to drain it occasionally.

Can I convert my existing coilovers to air suspension?

We offer air spring conversions for certain BC Racing coilovers. These replace the original steel spring with a suitable air spring while retaining the damper. Add your choice of management and air supply, and you have the makings of an air suspension setup. Browse the options in our Air Spring Conversions category.

What do the 1/4-inch and 3/8-inch line sizes mean?

A 1/4-inch air line is a common choice for everyday use. Larger 3/8-inch lines allow faster airflow, although the lines and fittings also take up more space. That can make routing them through tight spots a little more interesting. Both sizes do the same basic job.

Do I need two compressors or an enormous tank?

Not necessarily. The right setup depends on how often you adjust the suspension, the tank capacity and how quickly you want it to refill. A larger tank holds more air in reserve, so the compressor needs to run less frequently. It also takes more air to fill in the first place. If you regularly raise and lower the car at shows, extra tank capacity and compressor output can certainly earn their keep.

Can I build a system from universal components?

Yes, but your DIY skills need to extend beyond owning a promising-looking toolbox. Universal components need to work together, and there are several things to account for during installation. A vehicle-specific kit is an easier starting point whenever one is available.

Where should you start when choosing air suspension?

A good setup starts with knowing what you want from it. Easy everyday driving, a low show stance, or a bit of both? You can worry about the controller’s looks and fancy settings once the basic plan is sorted.

1. Start with the right struts and bags for your car

You’ll need a damper and air spring at each corner. Find a suitable kit for your car, paying attention to the body style, drivetrain and suspension layout. If the car has factory electronic damping such as EDC, you may also need an EDC Delete kit to prevent suspension faults.

Parking height and driving height are two different things. On the road, the tyres need clearance and the suspension needs usable travel in both compression and rebound. On many kits, the base height can be set mechanically by adjusting the strut length. The air springs then handle height changes within their operating range.

2. Choose management to suit how you use the car

• Mechanical paddle switches: the simplest manual arrangement, with air lines running directly to the switches.
• An electronic valve manifold: the valves are mounted separately from the control buttons. The adjustment can still be entirely manual.
• Automatic management: sensors and a control unit provide preset settings. Height sensing helps the system compensate for changes in load.

Some management packages bring together the controller, compressor, tank, valves and installation components in one compatible setup. Check the package contents and the features you want, such as memory presets, automatic raising at startup, phone control and the option to add height sensors later.

3. Make room for the air supply equipment

The air tank and compressor need somewhere to live. Common locations include the boot, a compartment beneath the boot floor or a recess behind the side trim. Leave room for air lines, wiring and maintenance, including easy access to the water separator.

Plan proper, secure mounting before you start fitting everything. A loose compressor is not an interior feature.

4. Build it to keep working

Route air lines away from heat, abrasion and moving parts. Check clearance around the air springs and tyres throughout the suspension’s travel. Follow the manufacturer’s wiring instructions and test the connections for leaks before hiding the installation behind trim panels.

A hose resting against a moving component might look harmless on installation day. Give it enough miles, and it can become a very different story.

Plan moisture removal from the outset. You need access to drain the tank and service the water separator. Moisture builds up in summer too, so make checking it a habit before the first frosty morning arrives.

Your air suspension checklist

• The car’s exact model, model year and suspension version.
• Suitable air springs and dampers for the required axles.
• Management with the features you want.
• A compressor, air tank and moisture removal.
• Compatible air lines, fittings and electrical components.
• Space for the equipment and a plan for installation and calibration.