Kitkajarrut

Kitkajarrut, or friction brakes, are a braking system that slows or stops a moving object by converting its kinetic energy into heat through friction between a brake pad or shoe and a rotating surface, such as a disc or a drum. The term reflects the Finnish word for friction (kitka) and brakes (jarrut). They are a fundamental type of braking used in many vehicles and machines.

Operation relies on applying a force to bring a brake pad or shoe into contact with a rotating brake surface. In hydraulic systems, pressing the brake pedal transmits fluid pressure to calipers or wheel cylinders, which clamp pads against a rotor (disc brake) or push shoes against the inside of a drum (drum brake). The resulting friction resists motion and dissipates energy as heat. The brake system usually includes a master cylinder or mechanical linkage, reservoirs or circuits for fluid, and components to transfer force efficiently and reliably.

Main types are disc brakes and drum brakes. Disc brakes use calipers to squeeze pads onto a rotor, offering strong braking, good heat dissipation, and precise control, often favored on front axles of modern cars. Drum brakes have shoes that press outward inside a rotating drum, providing robust parking braking and cost advantages on some rear axles or smaller vehicles. Various vehicles and machinery may use combinations of these designs, and performance is influenced by pad/shoe materials, rotor or drum condition, and cooling.

Materials for friction surfaces balance friction, wear resistance, and heat tolerance; modern pads avoid hazardous substances and aim for low dust and consistent performance. Regular inspection and maintenance—checking pad wear, surface condition of rotors or drums, and fluid integrity—are essential for reliable and safe braking.

See also: braking system, regenerative braking, brake fluid, brake maintenance.