Cable & Hydro disc brakes - how do they operate?

Disc brakes, both cable and hydraulic both work on the same basic principle of a lever transmitting force through a connecting link (a wire cable or a tube filled with fluid) which exerts pressure on a pair of brake pads which in turn clamp a rotating disc that is attached to the wheel's hub - just like the family car. As total weight has to be an important factor with bicycle disc brakes, their manufacturers have to be very creative with their design while having to work within some limiting factors. Hydraulic brakes work on the principles that fluids are not compressible and that fluids pressurized in a closed container transmit forces equally in all directions. Cable disc brakes work much the same as cable rim brakes but with exceptions that we will see later. This is how hydraulics work - a pull on the lever blade exerts pressure on a piston in a master cylinder (inside the brake lever). The piston then pushes on the oil in the brake line and the pressure travels down the line to ...  more