Air-Ride Suspension – What’s it all about?

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Air suspension, or “Air-Ride” can be found on many modern luxury, and customised vehicles. It’s know for providing optimum ride-height control and comfort. It has however been in existence for a surprisingly long time. Let’s explore a bit of the history of air suspension and how it has evolved to be used in the custom car scene.

Back in the 1920’s the first company to apply air suspension (originally for use in trucks) was a company called Tatra in Czech, however these early attempts proved unviable due to their complexity at the time, and reliability issues leading to air leaks.

These early attempts proved unviable due to their complexity at the time, and reliability issues leading to air leaks

Then, after the second world war and its use in Aircraft, GM introduced it in the Cadillac Eldorado Brougham in 1957. This however was again unsuccessful due to the complexity and cost, and was eventually replaced by regular coil spring suspension on all Cadillac’s after 1960.

The first production car in Europe to adopt air suspension was the Borgward 2.3L P100 in 1960, but sadly Borgward was suffering huge financial difficulties at the time and went bust three years later. It was starting to look like the future of this revolutionary design was very much up in the air.

But air-suspension was not dead yet, as another Germany company you might just be familiar with picked up the technology from Borgward, improved the design, and managed to make it cost effective too.

That company was Mercedes, and they subsequently used the technology in the 1963 “300SE” and “600” models. These cars were immediately hailed by the automotive press for their unbeatable ride quality, smooth handling, and ability to adapt to different road surfaces. Mercedes had finally cracked the nut of making air-suspension viable on scale, and millions of executive cars with air-suspension have been produced since.

How exactly does it work?

How air suspension works is very different to the usual coil springs, or leaf springs. In fact springs are replaced altogether with rubber ‘bellows’. These bellows, or “Air Springs” flex to allow movement and are pressurised allowing the weight of the vehicle to rest on them.

The pressure of these Air Springs is constantly monitored by the car for optimum performance. Along with pressure sensing, an air suspension unit comprises of an onboard compressor, air reservoir and air dryer. The spring rate is therefore determined by the air pressure, which makes it customisable for optimising ride-height, for tackling rough terrain, or providing incredible ride quality for say a chauffeur driven yacht on wheels.

The main benefits of an air suspension system over a conventional spring system include the constant ability to keep a car at the same height, regardless of the load on it, leading to optimum castor and camber geometry.

The main benefits of an air suspension system over a conventional spring system include the constant ability to keep a car at the same height, regardless of the load on it, leading to optimum castor and camber geometry; Also, a small point though it may be, but air-suspension is touted as being slightly safer as the load on the vehicle doesn’t affect the headlight angle and position when driving at night.

Overall driving dynamics are improved as the air suspension is more progressive, leading to a better response when driving at different speeds, for example resulting in a stiffer ride when cornering around a track, or comfortable and soft when cruising on low-speed road with bumps. With this, air suspension has a greater ability to absorb and transfer energy when driving in extreme conditions, being more reliable and safer over tougher terrain.

So is it worth shelling out for a conversion, or is it all ‘hot air’?

The custom car scene has adopted “Air Ride” technology in a big way, and many consider it the ultimate choice when choosing suspension mods.

Because of its adjustability at just the press of a button, a car can be lowered one minute for shows and track days and raised for normal everyday driving the next (without the time-consuming manual adjustment of a coil-over setup). A lot of custom car owners make the air lines, tanks and valves a design-feature of the car too – these systems can be extremely beautiful to look at as well as serving a genuine function.

There are a few things to consider when upgrading to air suspension, firstly being budget. A basic kit can set you back for around £2000 at the time of writing. For a fully Engineered setup which includes a height management and automatic levelling systems then it is easy to spend upwards of £3000 so it pays to take account of the value of the car itself before you consider upgrading.

This is not the only consideration, as like any mechanical or electrical system, faults can occur, and they can be pricey to fix when it comes to air-suspension. For example condensation in the air tanks can occur if you are not careful, and this leads to rust in the valves which can cause a world of problems and even lead to the whole system needing to be replaced.

An airbag and air-line needs to be looked after as well as a fuel line on installation, it’s important to make sure they don’t touch up against anything that will cause rubbing, and ultimately failure.

An airbag and air-line needs to be looked after as well as a fuel line on installation, it’s important to make sure they don’t touch up against anything that will cause rubbing, and ultimately failure. Some cars can have only one compressor installed for their air suspension system, however the bigger the car the more air and pressure is needed, and a dual compressor may be beneficial as it reduces the filling time of these tanks.

As a rule of thumb, for custom cars a three-gallon tank is big enough for a single compressor for either the front or rear wheels and a five-gallon tank for both front and rear systems. Another error that can occur is not installing fittings correctly, leading to leaks, and owners using inexpensive parts which simply do not last as long.

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