 Composite suspension
The older ones among you may recognize the slightly simplified ladder frame of a Citroen 2CV. Yes, it did not have a self-supporting body. Maybe that's why it turned out so airy. It sat bolted on a ladder frame with a cross-
shaped reinforcement in the middle.
This was covered by metal sheets from above and below, which we have reproduced here with a gray plate. The body had an opening there. So the top cover plate was used as a floor. At the front there was a rectangle to
accommodate the engine, final drive and transmission (in that order).
We left out the rear rectangle with the tank and the reinforcement, among other things, with the attachment points for the belts because it had no significance for the chassis. This consisted of two very stable tubes with
support arms at the ends. As can clearly be seen, the front ones deflect forward. It's less easy to see that the rear ones are oriented backwards.
Advantage of the method: The part of the chassis that actually ensures stability between the front and rear axles, with its heavy reinforcements, could be kept very short. The drive shafts with joints and sliding pieces showed
that the 2CV had a longitudinal front-wheel drive.
The VW Beetle also had such axles at the front in a slightly different shape, but they contained Ferdinand Porsche's famous torsion bars. Here the front one only houses the rack and pinion steering. On the left and right there
were 'pots' in the middle between the wheels. These each had two coil springs which were put under pressure by a rod with a spring plate.
The picture above shows one of the rods above the vibration damper. It is attached to the front left support arm in such a way that it is pulled out of the 'pot' when the left front wheel deflects. But that in itself would not be a
composite suspension. The only occurs when the 'pot' is not firmly connected to the chassis, as here, but can be moved forwards or backwards within certain limits combined with rubber buffers.
And what is composite suspension for? In the present case, the aim was obviously to achieve more roll-off comfort without having to 'pay' for it with even more side inclination. So, for example, if one axle deflects on its own
when the road is uneven, it essentially borrows some spring travel from the other through the combination. This changes when both axles deflects at the same time.
| Better than a passive stabilizer. |
It may be one of the secrets why such a light car had such a good suspension. By the way, the telescopic dampers were only added later. Originally, friction dampers were installed on the outside of the three-sided covers of
the cross tubes, some even with rubber-like coverings. They were fully effective as long as they were new.
But if the spring effect decreased due to pad wear, so did the damping. Only those who always readjusted had a non-rocking 2 CV. In addition, each wheel had a vibration absorber, i.e. a weight in a vertical, oil-filled 'pot' that,
with spring action, carried out exactly the opposite movement of the wheel suspension.
The composite suspension was also available as Hydrolastic from BMLC since 1963. Since the suspension here was carried out with liquid-filled rubber elements, one could connect these rooms of each one side
together, which, for example, this meant that the rear axle even lifted slightly, e.g. when the front suspension was compressed, which in this case should effectively prevent pitching, for example.
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