Air Suspension Basics
Air suspension components explained
An air suspension system has four core components. The air suspension itself (bags), a control system, air compressors, and an air tank. Each of these parts plays a specific role and understanding what each one does makes it much easier to buy the right setup and troubleshoot issues if they come up.
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Air suspension
Air suspension consists of the air bags, or air springs, that replace your factory coil spring suspension. Inflating or deflating your air suspension will either raise or lower your car. Most cars have air struts up front and either air struts in the rear or a separate spring and shock, also called a divorced rear setup.
Most air suspension comes in a few different styles that are dependent on the vehicle platform. They come in four main styles:
Style 01
Air struts
A combined unit with the air bag and shock absorber built together. Drop-in replacements for vehicles with strut-style suspension. Oftentimes air struts feature fully threaded damper bodies and camber plates much like coilovers.
Style 02
Single-convoluted bags
Features a single bellow style design. Offers a firmer ride over a shorter stroke (higher spring rates). Ideal sportier handling at lower ride heights and for tight spaces where vertical clearance is extremely limited.
Style 03
Double-convoluted bags
Also known as double bellow bags, these have become somewhat of an industry standard. Shaped like two stacked donuts, they offer a balance of travel, load capacity, and ride quality. A solid all around choice for daily drivers.
Style 04
Sleeve bags
Features a slim, tubular profile that easily fits into tight wheel wells and suspension clearances. Sleeve style bags feature an internal piston that causes the rubber to roll over itself upon compression, creating a narrow, but stable air spring.
When buying air suspension, it's always best to make sure it's vehicle specific. You can build up a custom setup but you'll be shooting in the dark. It's always best to go with a vehicle specific suspension setup that was designed for your car with proper spring rates, travel, and clearances in mind.
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Air suspension
Vehicle-specific air suspension designed for your exact year, make, and model.
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Buying new air suspension vs used air suspension
Is it better to buy new or save some cash and buy used?
Air compressor
The compressor pulls in outside air, pressurizes it, and pushes it into your tank for storage that will then be used for inflating your bags. Every time you air up, you use air and your tank pressure drops. Once your tank pressure drops below a certain level, the air compressor will automatically kick on and refill the tank. Typically most cars can get away with a single compressor, but running dual compressors has its benefits like faster fill speeds and redundancy.
Compressors are rated by a few key specs:
Spec 01
Max PSI
The maximum pressure of the compressor is rated for. Most air suspension setups run between a max of 150-200 PSI. Exceeding the compressor's max PSI can result in excessive wear and premature failure so we recommend 200 PSI compressors for our systems.
Spec 02
CFM (flow rate)
How much air the compressor moves per minute. A higher CFM means faster fill times but CFM is always tied to PSI, so you'll want to get a compressor that has higher CFMs in your refill range. CFM drops as pressure increases so watch out for "marketing" statistics that manufactures list - they don't always relate to real world use.
Spec 03
Duty cycle
How long the compressor can run before it needs to cool down. A 100% duty cycle means that the air compressor can run continuously. Lower duty cycle compressors need rest periods but this isn't an issue with any of the compressors that we carry for the setups that we offer.
Spec 04
Single vs dual
Running two air compressors cuts your fill time almost by half and it adds redundancy. If one of your compressors were to fail, you would have a backup that would still function. Dual compressors are more expensive than a single compressor and they take up twice the space, so it's really dependent on your setup.
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Air compressors
Single and dual compressor options for every build and budget.
Buyer guide
Single vs dual air compressors - which do you need?
A straightforward breakdown of when one compressor is enough and when two makes sense.
Air tank
The air tank stores compressed air that is then used for inflating your air suspension. Without a tank you would have to wait for the compressor to build air every single time you make an adjustment. Running a tank at 150-200 PSI allows you to inflate your air suspension multiple times before your compressor kicks on to refill your tank.
Think of the air tank as a buffer between the compressor and your bags. Basically the air compressor fills the air tank slowly, and the air tank lets you use that stored air instantly to inflate your bags, raising your car.
Here are a few things to consider when deciding on which air tank to go with:
Factor 01
Tank size
Air tanks are measured in gallons. The larger your tank, the more air it holds and the more times you can raise and lower your car before your compressor kicks in. Most setups run between a 2.5 and 5 gallon tank. Bigger is better in some situations but not always. The larger your tank, the more air you have to play with but the more space it takes up and the longer your compressor will run during fills.
Factor 02
Material
Aluminum air tanks are lightweight and resist corrosion. Steel tanks are heavier, can be cheaper, but they rust from the inside out which can cause debris to enter and damage the valves in your system. We don't carry steel air tanks and always recommend going with an aluminum air tank for these reasons.
Factor 03
Shape and placement
Tanks come in all sorts of shapes and sizes. Your available trunk space, tire well, undercar space, etc. will usually determine which shape makes the most sense for your build. As long as you measure, and mock up where you think you want to put your tank, you'll be good.
Factor 04
Port count
The port layout and the amount of ports on your tank will help determine what your management setup looks like. If you plan on getting fancy with a show trunk setup with hard lines and pedestal mounts for your components, going with a tank that has a symmetrical port layout will be more important than going with something "that just works".
What to look for: match tank size to how you use the car. If you're running air on your daily driver, a larger tank is usually the way to go since you're airing up and down more frequently. If you're building a show car that doesn't see a lot of road use, a smaller, more compact tank would be a good option. Stay away from steel, just go with an aluminum tank - you'll thank us later.
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Air tanks
Aluminum air tanks in a range of sizes and shapes to fit any build.
Control system
The control system is the brain of your air suspension setup and the portion that you'll be interacting with the most. It controls how and when the air moves between your air tank and each of your four bags. The quality of your control system has a bigger impact on your air ride experience than anything else. If you go with a premium controller that is designed to work well, you'll have much more fun than if you go with a cheaply designed system that's annoying to use.
Control systems range from simple to sophisticated - these are the four main categories:
Level 01
Manual paddle valves
The most basic option. Each paddle controls each corner of your car. You manually open and close valves to move air in and out of each bag. No electronics, no presets. Simple and reliable, but the install process is more complicated because it requires running more air lines than other systems and you need to run separate gauges to monitor your air pressures.
Level 02
Analog / switch box controllers
A step up from manual paddle valves. You get a physical controller and a separate valve block which allows for a cleaner / easier install with the same amount of air suspension control. Still no presets here and you're still required to read off of gauges to determine the height of your vehicle.
Level 03
Digital pressure-based control systems
The most popular choice for daily drivers and show cars alike. Digital pressure readings on the controller itself, user defined presets, easiest install - more plug and play than any other control system while including all of the bells and whistles. Pressure-based control systems are what we recommend for most people.
Level 04
Digital height-based control systems
All the features of a pressure-based control system with the added benefit of auto leveling. These systems use height sensors at each corner for the car and measure actual ride height rather than air pressure. When adding more weight to your car like passengers, the system auto detects changes in the height sensors and automatically adjusts your suspension. The fanciest option, but also one of the most complicated and expensive to install because of the physical height sensors on each corner.
What to look for: for most beginners, a digital pressure-based system checks all the boxes for convenience and cost. Height-based systems are the most impressive but they're also the most expensive and complex to set up.
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Control systems
From manual paddle valves to full digital management — find the right controller for your build.
Buyer guide
Best air suspension controllers
Full breakdown of every controller type — what each one feels like to live with day to day.
Air lines
Air lines are the tubing that connects everything in your air ride system together. From the compressor to the tank, and from your air management to each bag. Air lines come in all shapes and sizes, colors and materials but there are a few standards. Polyurethane air line is used for the vast majority of the system because it's flexible, reliable, and pretty inexpensive. Metal hard lines can be used to spruce up your management if you're interested in showing off your trunk setup, but they're more expensive, you'll need a pipe bender to route them and there's absolutely no point in running hard lines through your whole car instead of nylon. Unless you're into flexing on, fools of course.
Factor 01
Line material
DOT rated polyurethane air line is the standard. It's flexible, pressure rated, and durable. Avoid cheap generic plastic tubing that will crack and degrade over time. Hard lines are optional and should be reserved for shorter runs, making your trunk setup look more impressive.
Factor 02
Line size
Larger the diameter, the faster the flow. We recommend running 1/4" air lines for most cars because they're easier to run (more flexible) and digital systems have an easier time hitting presets with it. Larger air lines like 3/8" and 1/2" will follow faster but will also cause your vehicle to "jerk" more when airing up and down.
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Air line
DOT-rated nylon air line in 1/4", 3/8", and more — sold by the foot or by the roll.
Buyer guide
Best air line size for air suspension
How line diameter affects fill speed, pressure drop, and overall system performance.
Fittings
Fittings are the connectors in your system that join the air lines to each component. Fittings aren't viewed as the most impressive portion of your air ride setup, but they're one of the most important. A low quality or poorly sealing fitting will cause leaks, pressure drops, and slow fill times. The two main types of fittings are push-to-connect (PTC) and threaded. DOT approved push-to-connect fittings are the way to go. They easily connect to air lines and are used on industrial equipment and semis for millions of miles. Threaded fittings are pretty basic but sealing them properly is the most important thing to watch out for. A quality fitting is designed to last the test of time. Don't skimp out when it comes to fittings.
There are many different types of fittings that all serve different purposes - these are the four main things to understand when shopping for fittings:
01
Push-to-connect (PTC) fittings
The easiest fitting type to work with. Push the air line in and it locks - no tools required. The most common choice for DIY installs and complete kits.
02
Compression fittings
A little more complicated than PTC fittings since they require tools to install and uninstall air line. Compression fittings contain a compression sleeve / ring (ferrule), that squeezes down on the air line sealing the connection. These can be used with standard flexible air lines as well as hard lines but we generally recommend PTC overall with some exceptions like hard line setups.
03
Threaded fittings
Commonly used for the ports of an air tank and as adapters to resize fittings that are not the correct size for the port in mind. Require thread tape or sealant for each connection.
04
DOT-approved fittings
Fittings that are DOT-approved have passed rigorous tests and are the most reliable fittings you can find on the market since they are approved for industrial applications.
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Fittings
DOT-approved push-to-connect, compression, and threaded fittings for air suspension.
How all the components connect
Once you understand each part individually, the full system starts to make sense. Here's how it all flows together:
The compressor draws in outside air and pressurizes it. That pressurized air goes into the tank which acts as a reservoir. When you press a button on your controller telling the system to raise or lower a corner, it opens the appropriate valve and air flows from the tank into the bag, or out of the bag back through an exhaust port. The air lines and fittings are the plumbing that connects all of it together.
The whole setup is controlled by the control system, whether that's a series of paddle valves, a physical controller, a phone app, or a combination of these. From the driver's seat, you press a button and the car's air suspension inflates or deflates, changing the height of your vehicle.
A complete kit from Bag Riders bundles all of these components together, matched and tested to work as a perfectly seamless system for your specific vehicle. The main advantage of one of our built-in-house complete kits over piecing it together yourself is that you know everything is compatible before you start and that you have everything you need.