Nearly all Mercedes-Benz passenger vehicles have fully independent suspension, and many models make wide use of a double wishbone suspension in the front and a patented five-member multi-link layout at the rear. This state-of-the-art combination, along with the solidity and integrity of an extremely stiff body structure, helps provides responsive, safe handling and a smooth, well-damped ride at the same time. This unusual dual personality has prompted some journalists to characterize Mercedes as “a sports car disguised as a limousine.”
The S-Class and E-Class sedans as well as the CLS, CL coupe, SL coupe/roadster and new SLS AMG gull-wing coupe use a variation of the double wishbone in which each lower wishbone is split into two transverse links to provide better noise isolation, crash performance and kinematics. The Mercedes-Benz R-Class, GL-Class and M-Class have double wishbones at the front and a four-link suspension in the rear.
The SLK roadster, E-Class Coupe and cabriolets as well as C-Class sedans use 3-link front suspension and five-link rear suspension. The three-link front suspension feature control arms that are split into two transverse links, which contributes to kinematics, low noise and energy absorption in a collision. The G-Class is an exception to the rest of the Mercedes line in that it uses rigid axles at the front and rear for maximum off-road durability.
The double-wishbone design used on many Mercedes-Benz models provides precise wheel location and steering response, as well as low tire noise and vibration. Ride comfort is optimized because the shock absorber does not have to help locate or hold the wheel in place, and can therefore be “softer.”
The upper wishbone is mounted relatively high, and the lower one positioned at the lowest possible point so that locating points are spread far apart for sturdiness. Pivots for the two wishbones are offset to provide anti-dive characteristics. Front suspension geometry includes stabilizing caster and positive steering axis offset for good straight-line stability, neutral cornering and precise steering response, as well as a relatively small turning circle.
Currently used on most Mercedes-Benz passenger cars, the patented multi-link independent rear suspension is the result of analysis and testing which initially evaluated 77 different versions of eight basic types of suspension. Half of these went on to be tested in experimental models, but only one passed final road testing – the five-link design.
To evenly distribute all forces on the rear wheels, four of the links are transverse, while the fifth – the track rod – is longitudinal. The five-link suspension locates the drive wheels accurately to help ensure that the wheels point straight throughout their vertical range of travel and to help prevent unwanted rear wheel steering effect. This suspension design also uses the principles of kinematics and elasto-kinematics to take advantage of the tuned flex in the bushings of the five-link layout. Slight wheel angle movements produced by driving and braking forces are actually used to neutralize unwanted throttle steering. Its suspension geometry provides both anti-lift and anti-squat characteristics.
The five-link design requires little space, providing maximum trunk capacity and room for an ample fuel tank. In addition, it is one of the lightest suspension systems in current use, since only the lower transverse link must be beefy enough to handle bending stress. The other four links are subject only to stretch and compression forces, so they can be light, yet strong. Liberal use of aluminum alloy also helps keep unsprung weight to a minimum.
Source: Daimler AG