At the beginning of the motor car development the two rigid axles were taken over from the times of the horse and carriage. Also coming from this period, is the kingpin steering (Ackermann steering), which was also installed very early. In the period, up to the turn of the century, the engine was genarally moved forwards, and already before World War 1, the center of gravity, due to the smaller wheels and the altered chassis, was being lowered.
Right up to the end of the 1920s, racing cars capable of speeds of more than 200km/h, were still, normally, equipped with rigid axles in front and at the rear (see figure 3). Hydraulic shock absorbers, as we know them today, only finally established themselves after World War 2.
Due to the fact that, after 1945, first of all, the pre-war cars were still being built, the rigid front axles were still being used. The first new constructions changed this drastically. For the mid-range cars, it was now almost standard to install coil-sprung double wishbones in the front, combined at first, with leaf- and later coil-sprung rigid axles at the rear.
Compact cars appeared almost exclusively with rear-mounted engines and with the gearbox lying in front of the rear axle (figure 4), they had a tendency to oversteering, which could, nearly always, only be tamed by using stronger front stabiliszers. At the rear, the pendulum axle did the job. Mercedes installed these with only one joint, (indeed very much lowered) even in the upper- and sports car class (300 SL).
If one ignores the twin trailing arms and the crank steering of the VW-Beetle, from then on, there was only the the double-wishbone, which was replaced, in the economy and mid-range cars of the 1970s, always combined with the here, long established, self-supporting car body.
Unfortunately, the rear pendulum axle allowed a positive camber when slightly rebounding. Rear independent suspensions which avoided this, appeared, in a technically reasonable form, for the first time at BMW in the 1960s. Later the construction was adopted basically by all the manufacturers, even by those with the remaining rear mounted engines.
As early as 1959, the Mini from Great Britain, very, very slowly, spread to France and then later to Germany, making the front-wheel-drive and transverse mounted engine popular. When it got to VW/Audi, they invented the particularly effective and reasonably priced twist-beam rear axle which also enjoyed enourmous success all over the world.
Mercedes must be mentioned again, they wanted to build a Baby-Benz but because of the tank, there was insufficient space for the usual trailing arms. The multilink-axle was born, it didn't use up much space, however, it did call for a lot of criss-cross linkages.
By the 1990s it started getting complicated, because now the front-wheel drive was joined by the four-wheel drive. In this case, the rear axles became similarly complicated, like those of the front-mounted engine and rear-wheel drive.The keyword was now the multilink-axle. Small tie rods now appeared at the rear as well, to be able to exactly regulate the oblique running angle for a wheel at every angle of roll.
In the front, Audi even makes two single guides out of one wishbone, thereby relocating the swivel axle into the wheel. The steering was to become free of disturbing forces, a principle which was later partly retracted. In this case, the important elements are the, in the meantime, omnipresent, maintenance free ball-heads which, at the latest, in the 1970s, replaced the maintenance- and repair-intensive kingpins.
They are still found today in trucks, they are however, fitted with needle bearings. Here, the rigid axles also remain unchanged, apart from their complex guidance by the air suspension. Coaches, on the other hand, have followed the example of motor cars and light transport vehicles, even if only on the front axle.
In the meantime, the keyword is air suspension. It was tried out in the Mercedes 600, and then dropped again for a long time. Nowadays, it is, as an optional extra, almost standard in the luxury-class. Generally speaking, the electronics also control the chassis to a large extent, among other things, in the adaptive damping. It stiffens the suspension in milli-seconds and provides for more quietness, the same as the ESP, which recently, not only affects the braking system. 12/09