Bit Mouthpiece - Mouthpiece Thickness

Mouthpiece Thickness

A standard mouthpiece is 3/8 inch in diameter, measured one inch out from the bit rings (the area that usually come in contact with the bars). The common belief is that a thinner mouthpiece increases the severity of the bit, because it decreases the bearing surface and makes the bit "sharper." However, up to a point, some horses perform better with a thinner mouthpiece to a thicker one because there is less metal in their mouth and therefore more room for the tongue. This is mostly true if the rider has soft hands. Thinner mouthpieces are also preferable when using a double bridle, as the horse has even less room for its tongue with two bits in his mouth.

On the other hand, very thin bits (such as the twisted wire bits) have a marked severity over thicker bits. Some wire bits may come in a thickness as low as 1/16 inch, making them extremely severe to the point where it is easy for any rider to cut and ruin the horse's mouth, especially the lips. Many horsemen, even the most skilled riders, will not put such a harsh bit in their horse's mouths. Many equestrian organizations do not allow a bit to be 1/4 inch or thinner in diameter.

If the rider gives crude aids, it is generally best to pick a bit mouthpiece that is thicker. This may also be true with some horses with relatively thin bars, such as some Thoroughbreds.