The backing plate carries the friction material and acts as the frame for the pad. In order to avoid damage to the brake disc, the backing plate must be able to move within the caliper.
Backing plate – main features
Drill holes on the top radius from the BP:
These holes are designed to hold retaining springs, which act to push the pad away from the disc, when the brake-system is not in action.
Piston anti-twist protection:
To ensure that the piston stays in position, some applications include ‘pips’ – located on the lower radius or near to top radius.
Cranked slides areas:
These are designed to prevent the brake pad from dropping down between the disc and the caliper, if the friction material is worn.