Adjustable Dampers

HOW DIFFERENT ARE a set of aftermarket adjustable dampers to those fitted by a manufacturer? Apart from the fact that instead of simply pressing a button to change their setting you have to grovel underneath the car or fiddle around under the bonnet, the answer is very little.

- Will Beaumont

A conventional damper contains a piston that moves up and down inside a tube of oil. The oil passes through holes in the piston, and the speed at which the piston moves and the forces that are needed to move it are determined by a stack of shims above and below it. The shims on one side set the bump characteristics while those on the other side deal with rebound. The quantity, thickness, order, size and shape of the shims not only change the ‘stiffness’ of the damper, but also how quickly it reacts.