In 1930 the invention of the automobile lay more than 40 years in the past, and the roads had become considerably more suitable for fast car traffic than in the first quarter of the 20th century. Tire punctures were less frequent and suspension systems were safer and more comfortable, with brakes on all four wheels frequently being servo-assisted. Prince Heinrich of Prussia had invented the windscreen wiper to provide for good visibility in the rain. Direction indicators were mandatory, vehicles drove on the right, and from 1926 the steering wheel moved from the right to the left as traffic increased. It was now more important to have a good view of oncoming traffic rather than the side of the road.
Automotive engineering had changed in many important respects between 1900 and 1930. The chain drive was finally replaced by the shaft drive, which had first featured in the Benz Parsifal of 1903, the counterpart to the Mercedes Simplex.
The important feature of front wheel brakes appeared for the first time in a Mercedes production car of 1921 – first of all in the most powerful model, the 28/95-hp Sport, two years later in the basic version of the 28/95-hp model. From the summer of 1924, all Mercedes passenger cars were equipped with brakes on all four wheels. Thanks to the invention of the shock absorber, the comfort of car suspension systems, which were all based on rigid axles and leaf springs, was much improved though still far from perfect, particularly in the case of smaller, lighter vehicles. A swing axle first appeared on the Benz “teardrop” racing car of 1923.
On display at the 1931 Paris Motor Show was the Mercedes-Benz 170 with a completely new swing axle suspension, an important milestone in terms of ride comfort and handling safety. Of the four independently suspended wheels, the two at the front were located by a pair of transverse leaf springs, without a conventional axle, while each rear wheel was suspended from a swing-type axle half-shaft whose tubular sleeves were anchored to the frame by means of two coil springs each on the wheel side and mounted in journal bearings on the differential side. The result was a significant reduction in unsprung masses.
Independent wheel suspension, a firm principle for all Mercedes-Benz passenger cars ever since the introduction of the 170, established the brand’s reputation for producing outstandingly comfortable and safe vehicles. In 1933 this was followed by the 140-hp supercharged eight-cylinder 380 sports car, also with a full swing axle suspension, whose front wheels were for the first time located by parallelogram control arms with coil springs. This trailblazing design, separating wheel location, springing and damping from each other, became the standard front suspension system not just for Mercedes-Benz but also for numerous other manufacturers around the world.
In 1954, after countless refinements, the dual-joint swing axle introduced with the 170 in 1931 gave way to the single-joint swing axle which remained in the Mercedes range until 1972. It also had thrust arms and coil springs, and in the case of more powerful models also a horizontal compensating coil spring. A new dimension in ride comfort was opened up by a variant introduced in 1961, in which air chamber spring bellows replaced the coil springs. In 1968 the next step was the diagonal swing axle that was also supported on coil springs and ensured that track and particularly camber remained largely constant under spring compression and rebound.
At the end of 1982 the Mercedes-Benz model 190 of the compact W 201 series was presented.This was the direct forerunner of the
C-Class. It featured the unprecedented and sensational multi-link independent rear suspension. The optimal travel of the independently suspended rear wheels was achieved by distributing the forces and moments to five three-dimensionally arranged links, each of which was geometrically specialized for its function. Comfort and roadholding were optimized independently of each other. The rear suspension was complemented by a newly developed front suspension with transverse control arms, damper struts and separately located coil springs. The multi-link independent rear suspension was gradually introduced in all Mercedes-Benz sedans, coupes, convertibles and sports cars with rear-wheel drive.
A new S-Class joined the range in 1998. Instead of a classic springing and damping system using coil springs and gas-pressure shock absorbers, this featured the newly developed, electronically controlled “AIRmatic” (Adaptive Intelligent Ride Control), in which the air suspension and the adaptive damping system (ADS) form an integral unit, including individual, automatic level control on each wheel.
The result of numerous further developments to the multi-link independent rear suspension, now mainly made of aluminum components, was a significant step forward to higher-quality roadholding, ride comfort and handling safety. The front axle was likewise redesigned, with a four-link system of aluminum and steel replacing the previous double wishbone technology. Four components gave rise to the name: transverse spring links made of steel support the spring struts of the front axle. Radius rods at an oblique forward angle optimize front wheel location, assisted by upper wishbones as in the classic front suspension. Track rods link the transverse steering gear of the rack-and-pinion steering with the front wheels.
Dynamism and motoring pleasure – that was the motto with which the large Mercedes-Benz CL 500/CL 600 coupe claimed the peak position in 1999, and not just in German automotive engineering. Highly sophisticated technology, unequalled in this configuration by any other car worldwide, and a correspondingly innovative design characterized this exclusive car. The pioneering technology of the coupe had a new motoring experience in store for car drivers, which was particularly characterized by the world’s first actively controlled suspension system, Active Body Control (ABC), as an outstanding milestone of dynamic handling control and ride comfort. In this system hydraulically controlled servo cylinders in the spring struts work in unison with the passive shock absorbers and coil springs. The actively controllable elements reduce oscillating body vibrations up to five hertz, such as are noticeable in the form of body lift and roll on uneven road surfaces, heavy lateral roll on bends and bodywork diving under braking. In the Mercedes-Benz CL passive gas-pressure shock absorbers and coil springs are still responsible for handling higher-frequency wheel vibrations from six to 20 hertz, however their damping effect is less pronounced than in conventional suspension systems. This has a positive effect on vibration and road noise. Active roll stabilization renders torsion bar stabilizers superfluous.
With multi-link independent rear suspension, AIRMATIC and the ABC suspension system, Mercedes-Benz created outstanding conditions for maintaining its peak position in suspension engineering. These innovations are now found in various Mercedes-Benz vehicles on the market.
A new benchmark in terms of chassis technology was established in 2007 by the C-Class from the 204 series: The ADVANCED AGILITY package enables shock absorbers to be adjusted at the touch of a button – and at the same time to tune transmission shift characteristics. Also available is the AGILITY CONTROL package, a selective damping system that adjusts shock absorber power, steering and gearshift to suit different driving conditions.
A glimpse of the future is provided by the Mercedes-Benz F 700 research car displayed at the 2007 Frankfurt International Motor Show. With its active PRE-SCAN suspension, the car not only reacts highly sensitively to uneven patches of road surface but also acts in an anticipatory manner – enhancing both ride comfort and handling safety in equal measure.
PRE-SCAN uses two laser sensors in the headlamps as “eyes” which produce a precise picture of the condition of the road. On the basis of the image created by the laser sensors and the information about the road condition, the control unit develops a strategy for overcoming the obstacle concerned. In response, Active Body Control adjusts the damping of each individual wheel to a tauter or softer setting in advance and increases or reduces the load on the wheel by means of an active hydraulic system. The suspension is adapted to a given situation within fractions of a second. This results in a hitherto unprecedented level or ride comfort, combined with maximum handling safety.
.