Damping shims are designed to reduce or eliminate brake noise. The structure of a damping shim can be as follows:
In its simplest form a damping shim is designed as a flat, full-surface plate.
Other forms are attached to a carrier plate to additionally decouple it from the backing plate while braking.
Another version is attached to the carrier plate where it is in permanent contact with the backing plate in order to decouple both.
There are also forms with various cut-outs that utilise the pressure point displacement. The contact force of the piston is displaced from the centre of the brake pad towards the disc run-out. This ensures more uniform wear while at the same time reducing noise.
It is particularly important to ensure damping shims are firmly secured to prevent them from twisting. This avoids the shim coming in contact with and damaging the brake disc if the bonding fails. This is achieved by wobble riveting embossed geometry pins or with brake pad anchoring studs.