Bit (horse) - Design and Terminology

Design and Terminology

A bit consists of two basic components, the bit mouthpiece that goes inside the horse's mouth, and the bit rings of a snaffle bit or shanks of a curb bit, to which the bridle and reins attach.

All bits act with some combination of pressure and leverage, often in conjunction with pressure applied by other parts of the bridle such as the curb chain on the chin, noseband on the jaw and face, or pressure on the poll from the headstall. Particular mouthpieces do not define the type of bit. It is the sidepieces and the leverage these rings or shanks use to act on a horse's mouth that determines if a bit is in the curb or snaffle family, and has a great impact on the severity of the mouthpiece.

The mouthpiece of a horse's bit is the first factor most people think of when assessing the severity and action of the bit. Therefore, it is carefully considered when choosing a bit for a horse. Many mouthpieces are not allowed in certain competitions. Bit mouthpieces may be single jointed, double-jointed, "mullen" (a straight bar), or have an arched port in the center of varying height, with or without joints. Some have rollers, rings or small "keys" that the horse can move with its tongue. Mouthpieces may be smooth, wire-wrapped or otherwise roughened, or of twisted wire or metal.

Often, bits with shanks and single- or double-jointed mouthpieces are incorrectly referred to as snaffles. However, because of the presence of a shank, they are actually in the curb bit family.