Airmatic

Airmatic is the brand name Mercedes-Benz uses for its air-suspension system, a sophisticated alternative to the steel coil springs fitted to most cars. It exists to deliver the marque's signature blend of refinement, comfort and composure across a wide range of loads and speeds, qualities that are difficult to achieve fully with conventional springs whose stiffness is fixed once the car leaves the factory. By replacing those steel springs with controllable air springs, Airmatic gives engineers the freedom to adjust the suspension's behaviour and even the car's stance on demand.

The heart of the system is the air spring at each corner, a flexible rubber bellows that supports the car on a cushion of compressed air. An electric compressor and a network of valves and reservoirs raise or lower the pressure in each spring, allowing the system to alter the car's ride height and to keep it level regardless of how it is loaded. Working alongside the air springs are adaptive dampers, controlled by the Adaptive Damping System, so that spring rate and damping can be tuned together rather than in isolation.

This combination produces several practical abilities. The suspension self-levels, so a fully laden car sits at the correct height and rides properly rather than sagging at the rear. Ride height can be varied to suit conditions, raised for rough or steep surfaces and lowered at speed to improve aerodynamics and stability. Because air springs can be made progressive, the system can offer a softer initial response for comfort while firming up to control larger movements, and the adaptive dampers refine this further.

For the occupant the result is a notably cushioned yet controlled ride, with the body kept level through corners and under braking, and with the convenience of consistent ride quality whether the car is carrying one person or a full complement of passengers and luggage. The ability to adjust height also aids practicality, easing access and improving ground clearance when required.

The sophistication brings maintenance considerations. The rubber air springs, compressor, valve block and air lines are all wear items that can deteriorate with age and high mileage; perished bellows or a tired compressor are common faults on older cars, and repairs tend to be more expensive than replacing a simple coil spring. Owners of high-mileage examples should regard the system as something to inspect and budget for.

Airmatic is Mercedes-Benz's particular implementation of the wider concept of air suspension, comparable to systems marketed elsewhere as adaptive air suspension. Within the Mercedes range it is closely tied to the Adaptive Damping System that governs its dampers, and it sits below the more elaborate, hydraulically actuated Active Body Control in the hierarchy of the company's comfort and handling technologies.