Air suspension: have you really made the right choice?

As an active suspension system, air suspension has seen increasingly widespread adoption in luxury saloons, SUVs and commercial vehicles in recent years. This has led to a wide variety of air suspension products and retrofit solutions on the market. For vehicle owners and maintenance professionals alike, understanding how it works, its structural types and the key considerations for selection is essential to making the right decision.

 1. What is air suspension?

 Unlike traditional steel springs, air suspension supports the vehicle’s weight using compressed air and adjusts the suspension height according to the vehicle’s load and driving conditions. This design enables the vehicle to maintain a relatively stable ride height under varying loads and driving conditions, whilst delivering a more comfortable ride.

 Modern air suspension systems typically consist of several components:

 Air springs — provide the primary supporting force

 Air suspension shock absorbers / struts — control suspension movement and enhance stability

 Air compressor — supplies compressed air to the system

 Solenoid valves and valve bodies — control the flow and pressure of the air

 Air hoses and fittings — connect the entire air circuit

 Height sensors — detect vehicle body height

 Control module —— Controls system operation based on the vehicle’s status

 Therefore, air suspension is, more accurately, a system of interdependent components rather than a single part.

 2. What are the differences between various types of air suspension?

 Different vehicle models and usage scenarios place varying demands on the structure and design of air suspension systems. Air suspension systems on the market can be categorised into the following four types based on their structure, with significant differences in load-bearing capacity, installation space requirements and suitable vehicle models:

Ø   Bellows-type

 These utilise large, high-strength rubber air bags, offering strong load-bearing and support capabilities. With a robust structure, they are commonly used in vehicles with high load-bearing requirements. However, they are bulky and require significant installation space, making them unsuitable for compact chassis structures

Ø  Coil Spring Bellows

 Combines mechanical coil springs with an air spring structure, offering both the structural stability of mechanical springs and the pressure adjustability of air springs. This type of system strikes a good balance between ride comfort and handling stability, and is commonly found in mid- to high-end passenger cars and SUVs. The structure is relatively complex, and component and maintenance costs are higher than those of single-structure solutions. 

Ø  Rolling Lobe

 This structure is more compact and can accommodate suspension locations with limited space. Whilst its load-bearing capacity is lower than that of the previous two types, it offers greater flexibility in adaptation and is frequently used for air suspension retrofits in saloons and small cars.

Ø  Air Suspension Strut

 Combines the air spring with the shock absorber to form a complete suspension assembly. This design reduces complexity during installation and calibration, and is a common configuration in many passenger car air suspension systems.

Ø  Electronically Controlled Air Suspension

 These systems use height sensors and electronic control modules to monitor the vehicle’s status in real time, automatically adjusting air pressure and vehicle height. Such systems typically allow the driver to actively select different suspension modes (such as road mode or off-road mode) according to road conditions, enabling the driver to achieve more appropriate suspension performance in different driving environments. This is currently the most technologically advanced type of air suspension. However, maintenance and calibration costs are relatively high.

 3. Is it really necessary to fit an air suspension system?

 Fitting or replacing an air suspension system will have a substantial impact on the vehicle’s overall dynamic characteristics. It is recommended to assess this from the following perspectives:

 Ride comfort: Air suspension offers superior shock absorption and filtration compared to most passive suspension systems

 Height adaptability: The vehicle’s ride height can be adjusted according to driving scenarios (urban commuting, motorway cruising, complex road conditions)

 Load adaptability: Support pressure can be increased when the vehicle is fully loaded or carrying additional passengers, preventing excessive suspension compression

 Component durability: More even weight distribution helps reduce the rate of wear on the suspension system and associated components

 If the vehicle is frequently subjected to varying loads, or if there are high demands on ride comfort, fitting an air suspension system offers significant practical benefits.

 4. When selecting air suspension components, do not base your choice solely on the vehicle model

 This is a point that many buyers tend to overlook.

 Even for the same vehicle model, different model years, engines, specifications, or even suspension systems may require different components. Furthermore, whilst air suspension kits from different manufacturers and models may appear highly similar in appearance, differences in fitment precision, materials and after-sales support will directly affect performance and service life.

 Therefore, when selecting air suspension components, it is advisable to verify the following:

• Vehicle compatibility information

 Vehicle model + year + VIN / chassis number + OE number + installation location

 If possible, providing photographs of the original parts will also be helpful.

 In particular, when purchasing assemblies such as air suspension struts or air shock absorbers, relying solely on the vehicle model name can easily lead to compatibility issues.

• Product Classification: Replacement vs Upgrade

 Replacement kits: Designed to restore the original suspension performance and geometric parameters, these are suitable for repair and replacement when the original air suspension has aged or failed.

 Upgrade kits: These add functional features to the original equipment (such as Bluetooth control modules and programmable height presets) and are suitable for modification requirements where greater customisability and convenience are desired. There is a fundamental difference in the design objectives of these two product types; you should clarify your own requirements before selecting a model.

• Materials and Warranty

 The material grade of core components, such as air springs and air pumps, cannot usually be determined directly from product images. Warranty terms serve as a key external indicator for assessing a manufacturer’s confidence in their products and the standard of their quality control—manufacturers willing to offer longer warranty periods typically maintain stricter quality control standards during production.

 Air suspension components do not necessarily need to be replaced as a complete set.

 Depending on the vehicle’s structure, product design and actual requirements, you may choose:

1. Individual air springs

Suitable for applications requiring the replacement of specific components.

2.  Air suspension shock absorbers / struts

 Suitable for vehicle models with an integrated design, allowing the complete suspension assembly to be replaced directly.

3. Complete suspension assemblies

 Complete assemblies are also an option for customers wishing to simplify installation and improve replacement efficiency.

 Which option is most suitable depends on the specific vehicle model and actual requirements.

 5. Points to note during installation

 For most vehicle models, the installation of air suspension is of moderate difficulty and can be carried out by a qualified mechanic or an ASE-certified workshop, without incurring excessive labour costs. If a quote is significantly higher than market rates, it is advisable to shop around for alternative quotes.

 Car owners with some mechanical repair experience may also consider carrying out the installation themselves. Compared to replacing passive shock absorbers, the installation of an air suspension involves slightly more steps; however, provided standard installation procedures are followed, it is a repair task that can be undertaken independently.