Too Many Choices
A popular feature of many tack shops is the "Bit Wall". This is usually a rather intimidating array of different types of bit, each with different features designed to work in a slightly different way. Trying to decide which is the right bit for your horse can be confusing, but when you look closely, you'll see that there are only two basic types of bit: the Snaffle Bit and the Curb Bit.
Most people assume that because the snaffle is usually a jointed bit and the curb usually is not, the mouthpiece is what determines whether a particular bit is a snaffle or a curb. However, according to veteran horse trainer, Jessica Jahiel, the difference between snaffles and curbs has nothing to do with the mouthpiece. The difference between the two types of bit is that the snaffle is a non-leverage bit and the curb is a leverage bit.
What Does That Mean?
On a snaffle bit, the rein attaches directly to the mouthpiece. The bit acts with a nutcracker action (provided it is jointed) on the bars of the mouth (the area of gum between the front and back teeth), the corners of the mouth and the tongue. As the rider takes a contact on the rein, the horse feels an equal amount of contact on the bit in his mouth.
On a curb bit, the rein attaches to a shank or cheekpiece which adds leverage. When the rider takes a contact on the rein, the horse feels a greater amount of contact, depending on the length of the shank. Following the basic physics of leverage, the longer the shank, the greater the leverage. The curb bit works on the bars of the mouth, as well as under the chin (by way of the curb chain which is attached to the bit) and over the poll.
Types of Snaffles
The gentlest type of snaffle bit is the Eggbutt snaffle. The name comes from the somewhat egg-shaped connection between the mouthpiece and the bit-ring. The mouthpiece of an eggbutt can be made of a variety of materials (as can any bit), including copper and synthetic (either solid or covered). The reason this bit is so gentle is that it doesn't pinch the corners of the mouth.
Another style of snaffle bit is the D-Ring snaffle. The name is self-explanatory in that the ring of the bit is in the shape of a "D".
In the Loose-Ring snaffle, the mouthpiece is attached to a full-round ring, and can slide around on it, allowing the bit to lay in the most natural position, whatever horse it is used on.
Some snaffle bits, such as the Full Cheek Snaffle, have cheek-pieces which prevent the bit from being pulled through the mouth.
Types of Curb Bit
A basic Western Curb Bit has a gently ported mouthpiece and shanks to which the reins attach. As the rider takes a feel of the reins, more leverage is exerted on the horse's mouth and also on the poll (where the bridle goes over the head, behind the ears). By increasing the amount of port on the mouthpiece, pressure is applied to the roof of the mouth also. Since Western horses are ridden on a loose rein, the longer shank allows the rider to utilize the leverage by giving extremely light rein aids and attaining the same result as a rider using a snaffle on a firmer contact.
In the English Curb Bit the port can also vary in severity. In general the shanks on English bits are shorter than on Western bits - four to five inches on an English bit as opposed to up to eight or nine inches on a Western one. The English Curb bit is often used in a double bridle. In the double bridle, two bits are actually used. One is the curb, called the Weymouth and one is the snaffle, called the Bridoon. Both of these bits are used together to refine the aids in the higher levels of dressage competition.