THE ‘W HY AND W HAT’ OF SUSPENSION

THE only time we think about our cars’ suspension is when it starts to perform badly. Squeaking, groaning, shaking and swaying are not lewd terms but what happens when we encounter bad suspension. The only remedy is replacement of worn parts but it is interesting to find out about the why and what of car suspension systems.

Suspension would not be necessary if roads were perfectly flat but even the best built highway has undulations and imperfections. It almost certainly has curves and turns as well. The suspension of any car has to deal with forces from bumps as well as forces from cornering. The study of these forces is called vehicle dynamics and is mostly centred on how to maintain the tyres contact and traction with the road surface.

The suspension of a car is actually a part of the chassis and consists of three fundamental components: springs, dampers and anti-sway bars. is the leaf spring which is several layers of metal bound together in different strengths and lengths. Thirdly, there is the torsion bar, a length of steel anchored on one end which works as a spring when twisted by a lever attached to the wheel. Finally, there is air springing, which uses the compressive qualities of air inside a cylinder.

Springs are simple devices designed to absorb the movement of the cars’ wheel but springs alone cannot provide a perfectly smooth ride. That’s because springs do not dissipate the force acting upon it. This is the job of the damper or shock absorber.