Brake Caliper

The brake caliper is the part of a disc brake that sits over the edge of the brake disc and does not rotate. When you pull the lever or press the pedal, hydraulic fluid pushes one or more pistons inside the caliper, and they squeeze the brake pads against the disc.

Calipers are either floating (pistons on one side, the body slides on pins) or fixed (opposed pistons on both sides). Many modern sports bikes use radially mounted four-piston monobloc calipers for stiffness and feel.

Keep calipers clean and check them when you change pads: dirt and corrosion on the pistons can make them stick, causing a dragging brake, uneven pad wear or a spongy feel. Replace brake fluid at the interval in your service manual and always use the DOT grade stated on the reservoir cap.