WARM SPRINGS, HEATED DAMPERS AND HOT FLUIDS

Even in summertime, how heat affects the replaceable chassis components is not that obvious, but Rob Marshall learns that it is very much relevant

Every day is a school day, as the cliché goes, but the more interesting motorcar facts tend to be those that are not noticed. While hardly any attention is given to it, heat, for instance, is very much relevant to springs and shock absorbers. Yet, Meyle is the first specialist to pull us up on our vocabulary. The company highlights that ‘shock absorber’ is inaccurate terminology, it should be referred to as a vibration damper. With our knuckles rapped justifiably, the company is correct and, hence, why we recommend that garages also ditch the term ‘shock absorber’ from their vocabulary.

To explain why, energy that is introduced to the vehicle by a pothole, for instance, has to go somewhere; it cannot just disappear. Dampers achieve this by damping the vibration using friction, which creates heat. While this is not obvious on everyday road-legal vehicles, it explains why dampers in some competition vehicles possess heat exchangers. Even so, the sealed nature of dampers means that their inner workings remain mysterious to many technicians. We know that the dampers work with springs to keep the wheels in contact with the road and, therefore, maintain driver control, but how this is achieved is not so clear. The damper is a precision component, which utilises a piston that forces oil through fine internal chambers. The resultant bottlenecks slow piston movement and the friction warms the fluid. This heat energy is then dissipated within the damper. Meyle also says that dampers tend to be warmer after a journey – not that anybody checks –but it is still an interesting fact.