Wheel guidance is considered to be the most multifaceted component in the development of the suspension. It has to do with the development of the springing, or perhaps it's the other way round. Rigid, leaf-sprung front- and rear axles were almost undisputed until the 1930's. The slowly developing front-wheel drive forced the first changes to be made. The front axle was slowly changed over to independent suspension and that, from the top of the range down to the economy class and was applicable for all types of drive-trains.

There had already been the occasional models, e.g., the Lancia Lambda. Individual manufacturers however, stuck with the rigid front axle till shortly after the Second World War. Then however, they finally disappeared. Regardless of whether at first the rear-wheel- then later the front-wheel drive, what dominated was the double wishbone and with the development of appropriate shock absorbers and the ability of the coachwork to share more of the load, also the McPherson strut, at least in the somewhat lighter cars.

In the case of the rear axle, it was a bit more difficult. Certainly, in the case of front-wheel drive it was free running and could take on almost any possible form, quite often of course, the shape of the lighter rigid axle. Indeed, in the 1950's there were hardly any frontwheel drives and the Mini would only begin to spread the word in the beginning of the 1960's. Thus, the leaf-sprung rigid axle dominated in certain mass produced vehicles for still some time to come. Even the first racing cars by Ferrarri, which was only founded after the Second World War, still relied on this construction. A top of the range Mercedes only differed from this through having a floating axle with a particularly low-lying universal joint.

Of course, at that time there were a lot of vehicles with rear engines, their driven rear axle was also based on the floating axle principle, indeed, with two universal joints. In the front the VW Beetle differs from all others by having two short trailing arms. While we're on the subject of special features, in the front, the Citroen 2 CV had something similar, in fact it had a pushed trailing arm on each side. However, even though it was a pre-war construction, it already had coil springs, which one could not say about the VW with it's torsion bar suspension.

So, what do we have?, a great deal of smaller cars with rear engines and very few with front-wheel drive. The double wishbone axle, probably from Chrysler, which was developed in the 1930's dominated in all vehicles except the Beetle and the 2 CV. In the 1960's a slight correction was made to the vehicles with rear-wheel drive rigid axles. Throughout the industry, they were, at the latest now, changing from leaf- to coil- springs. There are various opinions - up to four trailing arms -, about the thrust-piece on the drive shaft. Partly different is also the lateral guidance through Panhard-rods or wishbones (Alfa).

Sports cars, like e.g. the E-Type Jaguar and the Jaguar saloons had independent suspension, even if, in this case, each rear wheel was guided through an arm and the drive shaft. In the 1970's the semi-trailing arms made their final breakthrough, although they were in fact, introduced much earlier by BMW. In the beginning there were still far to few front-wheel drives, this changed however, first through British and then through massive French influences. In the middle of the 1970's the VW concern brought out the lightweight torsion-beam-axle, a real eye-opener, so much so, that it was copied for almost all compact cars, even by the forerunners from France.

One important development should not be forgotten, the rubber-encapsulated ball-joint. It revolutionized the guided front axle, allowed us to forget about greasing and through the falling away of the stub axles, it reduced the unsprung mass. The development of wear-resistant homo kinetic drive shafts must also be mentioned, without which the concentrated emergence of the front-wheel drives and also the independent suspension in rear-wheel drives would not have been possible. By the way, the rear engine disappeared around this time and is only kept alive for the enthusiasts of Porsche 911's The technologists there can still find ways and means to maintain it's competitiveness.

Oh yes, I almost forgot about one particular construction. To enable larger cars to profit from the lower unsprung masses, there is, e.g., in the big Opel, a converted DeDion axle. This is one of their last comebacks, since the trend is clearly in the direction of the multi-link axle, by the way, in the meantime, also for front-wheel drives. This has something to do with the shifting of the fuel tank, for safety reasons, to under the rear seats. There is less space for the semi-trailing arms. Thus, we've arrived at the almost completely programmable suspension, particularly at the rear because of the optional all-wheel drive, but also in front-wheel drives.

In this short summary there is a lot which hasn't been mentioned. Even the grease-gun could be put back in the cupboard, also because of the, at least in standard cars, complete encapsulation in rubber - or better still in plastic sleeves. These, together with possible sub-frames enable the almost complete separation of the suspension from the rest of the coachwork. Only towards the end of the last century would these bearings - called 'silent blocks' be distributed around the entire construction and given various qualities, which would have different effects on the springing.

Nowadays, one can reproduce almost every road or race-track in the in-house test studio. One can call up enormous data-blocks full of experiences. In the 1970's that was much different. One attempted, through researching film material, to make the advantages of negative steering-roll radius clear. Although, even today, where a great amount of test-kilometers are still necessary, the chances of coming across a completely screwed-up suspension are substantially lower. In sports cars the engineers seem to be very interested in the qualities of the suspension with deactivated ESP (electronic stability control). There's probably no chance that the manufacturers could simply leave out the switch-off possibility and only allow it to be de-activated for racing purposes.

Thus, we come to the electronics. In the meantime, they also control the suspension, just like the other areas of the motor car. Shock absorber hardness, the pre-tensioning of the springs and passive or even active ESP. Have we forgotten anything? Yes of course, in fact a great deal, e.g., for controlling the downhill driving in off-road vehicles, the stopping on an uphill slope, the anti-slewing when towing a trailer, just to mention a few more. Actually, the ABS-system should also have a place of honour in this list, since it is more a steering- than a braking assistant. We are however, keeping a chapter open especially for the braking system. 03/17

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