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Coil vs. air suspension: advantages and disadvantages

Coil vs. Air Suspension: Which One is Right For You?

by AAS Team on October 04, 2021 Categories: Tech Talk

When it comes to deciding between coil vs. air suspensions, there are a number of factors to consider. Among those factors are comfort, longevity, and cost. Coil suspensions and air suspensions both have unique advantages and disadvantages, so we’ve decided to break down those differences to help you get a better idea of where you stand on coil vs. air suspensions. 

What is a coil suspension?

A coil suspension is a traditional car suspension that uses mechanical resistance from springs to keep your car at the proper ride height. This is known as a passive suspension system since it has no moving parts and does not actively respond to changes in the road.

Coil suspensions are made of just a few independent components, including:

  • Coil springs. The metal springs that fit around the struts are referred to as coils. These coil springs are made of durable metal and their resistance can be tuned to adjust the amount of give in the spring, affecting the amount of travel at that wheel.
  • Struts. Also known as dampers, struts are the part of a coil suspension that carries most of the weight of your vehicle. These are rigid, metal tubes that sometimes have compressed gas such as nitrogen inside them.
  • Bump stop. A bump stop is exactly what it sounds like. Usually made of firm rubber, the components keep your strut from bumping up into your vehicle.
  • Mounts. The mounts in your coilover suspension are what actually holds your suspension in place. These are usually made of a strong metal and require nuts, washers, and bolts to secure them.

What is an air suspension?

An air suspension is a kind of active suspension, responding to changes in the road by adjusting your vehicle’s ride height. Instead of metal coils and struts, an air suspension uses a complex network of moving parts, computers, and compressed air to hold your car up.

These are just some of the components that make up an air suspension:

  • Air springs. Also called air bags or air struts, air springs are usually made of flexible rubber. They inflate and deflate with pressurized air to respond to changes in the road and keep your vehicle at the proper ride height.
  • Suspension control module. Your air suspension’s “brain” is a small computer that analyzes information about your car’s ride height and processes that into signals to send to the air compressor.
  • Air compressor. This compressor is a small, computer-controlled version of the kind of air compressor you see in auto shops. It takes signals from the suspension control module and uses them to generate the required amount of pressurized air needed to inflate your car to the right ride height. It also sends this air to the air springs.
  • Ride height sensors. These small mechanical pieces constantly take readings of your vehicle’s ride height at each corner and send that information to the suspension control module.
  • Air lines. Rubber or plastic hoses carry pressurized air from the compressor into the air springs.

Coil vs. air suspension: advantages and disadvantages

As we mentioned earlier, each suspension style comes with its own unique advantages and disadvantages in several categories.

Here’s a breakdown of coil vs. air suspensions when it comes to a few different factors.

Coil vs air suspension: comfort

It’s easy to think that air suspension would have a clear advantage when it comes to comfort, and in many cases that would be correct. Because air suspensions are active suspensions, they can adjust to changes in the road, allowing for an incredibly smooth ride—as long as they are working properly. Once an air suspension starts to fail, that smooth ride can turn into one that’s uncomfortable and even unsafe.

Coil suspensions don’t have the ability to adapt to road conditions, which means drivers tend to feel more bumps and dips. However, when properly tuned and rated, coil springs can provide the right balance between support and give that makes for an incredibly comfortable ride. But not every manufacturer takes the time and spends the resources needed to do this.

Advantage: Air suspensions, but only while they last.

Coil vs air suspension: comfort

Coil suspension vs. air suspension: longevity

Air suspensions might score well when it comes to comfort, but when it comes to longevity, they mostly come up short. It’s not specific to one manufacturer or another, either. That’s because the complex, interconnected nature of air suspensions and their reliance on moving parts and computer-controlled components makes them very vulnerable to failure.

Each piece in an air suspension system is dependent on the others to work properly. If an air spring has a leak in it—one of the most common air suspension problems—the ride height sensors, other air springs, and especially the compressor pick up the slack. This leads to early failure of each of these components, and not just the original air spring.

By contrast, coil suspensions are simple and made of rugged, durable materials. This is especially true when you buy your suspension from a reputable manufacturer. Unfortunately, some manufacturers cut costs by using cheaper alloys. American Air Suspension, on the other hand, only uses robust, high-quality steel for all of its manufacturing, down to the nuts, bolts, and washers.

Without the need for moving parts, there’s much less that can go wrong with a coil suspension. And since those static parts are made from some of the most durable materials on earth, they’re much less likely to fail. When it comes to coil suspension vs. air suspension in terms of longevity, there’s no competition.

Advantage: Coil suspensions, by a longshot

Coil suspension vs. air suspension: cost

Air suspensions provide a great ride while they last, but that ride comes at a cost. If you’ve ever tried to replace air suspension components or get your air suspension repaired at the dealership, you know just how expensive it can be.

As you can imagine, highly-specialized computers like your car’s suspension control module can be costly, along with its air compressor. But it’s the air springs that often cause the most sticker shock—and that most often wear out. Just one air spring can cost you well over $1,000, depending on the make and model of your car. Since those air springs wear out at about the same rate, you’ll need to replace all four sooner or later.

But despite being constructed of more durable materials, a high-quality coil suspension kit that can replace the suspension at all four wheels may cost you not much more than just one air spring.

That’s because they don’t use complicated networks of computer-controlled components, moving parts, and components made of flimsy materials. Instead, they use high-quality steel and old-fashioned mechanical resistance. Because of this, you can install a long-lasting, high-performance suspension replacement kit without breaking the bank.

Advantage: Coil suspensions, and it’s not even close.

Coil suspension vs. air suspension: the verdict

There’s certainly something wonderful about the smooth, cloud-like ride of a brand new air suspension. But one it starts to wear down, that does away and what you’re left with is problems. Potentially costly problems.’

We prefer coil suspensions due to their longevity and cost value  - especially in older vehicles.