Coilover is a dirty little word in the automotive media
landscape. It’s a word that conveys images bone shaking ride quality and iffy
aftermarket quality. It is then always a quite a satisfying surprise when
reading a review about a performance car that is equipped with aftermarket
coilovers from the factory. The reviews will boast of new found levels of body
control and grip alongside a firm but refined ride.
Read the review of the coilover-equipped car versus that of
the car riding on the OEM suspension and the difference may well be night and
day. This strikes at the very heart of a large sect of the automotive media
that immediately looks down upon anything that isn’t made by an OEM manufacturer,
or that somehow engineers at large OEMs – folks who are under pressure and on
tight budgets to deliver impossible targets – are somehow able to magic together
an impeccably good suspension package.
Have you ever seen an OEM damper? Even on the most high-end
cars they are ugly, produced by the hundreds of thousands cylinders with imprecise
welds and questionable fit and finish. On a BMW M3, an OEM damper probably
costs BMW $10. That is the kind of technology that these high performance cars
are using.
That being said, all it takes is one negative experience
with coilovers and all enthusiasm for them can cease. And in addition to that
being said, there are some awful aftermarket coilover options out there. I’ve
seen kits for £300 and in a situation like that, you are genuinely better off
driving on failed OEM dampers at that point.
This cheap crap is a real shame, as the high-quality
coilover kits are stunning, precision designed and built pieces of engineering
that channels hundreds of years of collective racing experience into a single
product.
What makes high-quality coilovers particularly good is the
ability to choose spring rates. Most OEM suspension makes use of what are known
as progressive-rate springs. These springs are designed to offer a variety of
spring rates as the spring compresses during driving. The idea is that fast
impacts cause only the softest part of the spring to compress, which gives good
ride comfort, and then as the suspension loads up, the spring compresses and
the stiffer section gives improved body control and precision.
In reality however, you are left with a spring that provides
neither good ride comfort, or excellent grip and control at the limit. The fact
that the internal valving of the accompanying damper does not vary with the
spring also complicates things.
However, with a set of coilovers you can choose both the
spring rate and then alter the characteristics of the damper in response to
this. With a bit of fine-tuning you can achieve a ride that is soft and compliant
but also controlled and accurate in all situations. Not only does this give
more grip and driver confidence, but it also improves safety due to the higher
levels of grip available in all situations.
So let’s not knock the coilover, and instead realise that
the quality units are better than anything an OEM could ever make.
Kerbside 