Pelham bit
From Wikipedia, the free encyclopedia
A pelham is a type of curb bit used when riding a horse. It consists of a mouthpiece, a shank, a curb chain, 2 rein rings per side on the shank, and one cheekpiece ring on the top of the shank. The top rein ring is located next to the mouthpiece, as in a snaffle, and the rein that attaches to it is thus called the snaffle rein. The lower ring, at the bottom of the shank, is called the curb rein due to its curb action.
Due to the severity of the curb in relation to a snaffle, it should not be used by novice riders. Double reins are also more complicated for a novice to handle. The pelham should be ridden mainly off the snaffle rein, with the curb rein only coming into effect when needed. Often, a bit converter, also known as a pelham rounding, is used so a pelham can be used with only one rein. This is especially helpful in the cross-country phase of eventing, so that when the reins are slipped only one must be shortened. However, use of a converter is illegal in most other horse show classes. If used with two reins, the snaffle rein should be wider to help distinguish it from the curb.
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[edit] The action of the Pelham
A pelham works on several parts of a horses mouth, depending on which rein is applied.
- The bars: applied by the mouthpiece, and directly related to the length of the shank of the bit. The curb chain and a high port can also increase the pressure placed on the bars of the mouth.
- The tongue: applied by the mouthpiece, with the pressure related to the thickness and type of mouthpiece.
- The roof of the mouth: only applicable if the mouthpiece of the pelham has a high port, or if it is jointed.
- The poll: severity is directly related to the length of the upper shank in relation to the lower shank. All pelhams apply at least a little pressure on the poll.
- The chin groove: pressure applied by the curb chain when the curb rein is used.
- Side of the jaws: a pelham may add some pressure to the sides of the jaw due to its length.
[edit] The Shank
- See also: bit shank
A pelham is a leverage bit, meaning that is multiplies the pressure applied by the rider. Unlike a snaffle bit, the curb rein can amplify the rein pressure several times over, depending on the length of the pelham's shank. Shank sizes vary from the Tom Thumb (2 inches long) to several inches, although most are less than 4 inches (100 mm).
The relation of the upper shank (cheek)--the shank length from the mouthpiece to the cheekpiece rings-- and the lower shank--the shank length from the mouthpiece to the lowest rein ring, is important in the severity of the bit. If the bit has a 1.5" cheek and a 4.5" lower shank, thus producing a 1:3 ratio of cheek to shank, and producing 3 pounds-force of pressure on the horse's mouth for every 1 pound-force (3 newtons per newton) placed on the reins. If the bit had 2" cheeks and 8" shank (ratio of 1:4), the bit will produce 4 lbf (18 N) of tension for every one applied by the reins (4 N/N). Regardless of the ratio, the longer the shank, the less force is needed on the reins to provide a given amount of pressure on the mouth. So, if one were to apply 1 lbf (4.4 N) of pressure on the horse's mouth, a 2" shank would need much more rein pressure than an 8" shank to provide the same effect.
A long lower shank in relation to the upper shank increases the leverage, and thus the pressure, on the curb groove and the bars of the mouth. A long upper shank in relation to the lower shank increases the pressure on the poll, but does not apply as much pressure on the bars of the mouth.
However, longer-shanked bits must rotate back further before applying pressure on the horse's mouth than shorter-shanked bits. Therefore, the horse has more warning in a long-shanked bit, allowing it to respond before any significant pressure is applied to its mouth, than it would in a shorter-shanked bit. In this way, a longer shank can allow better communication between horse and rider, without increasing severity. This is also directly dependent on the tightness of the curb chain.
[edit] The Mouthpiece
- See also: bit mouthpiece
The pelham's mouthpiece controls the pressure on the tongue, roof of the mouth, and bars. A mullen mouth places even pressure on the bars and tongue. A port places more pressure on the bars, and provide room for the tongue. A high port may act on the roof of the mouth as it touches, and will act as a fulcrum, amplifying the pressure on the bars of the mouth.
Jointed mouthpieces increase the pressure on the bars as the mouthpiece breaks over in a "nutcracker" effect. Unlike a jointed mouthpiece on a snaffle bit, a jointed mouthpiece on a bit with shanks, such as the pelham, can be quite severe in its effect, particularly if the pressure from the shanks causes the joint of the bit to roll forward and press the tip of the joint into the tongue.
[edit] The curb chain
The curb chain applies pressure to the curb groove under a horse's chin. It amplifies the pressure on the bars of the horse's mouth, because when it tightens it acts as a fulcrum.
[edit] Use of the Pelham
The pelham is most commonly seen (although not nearly as much as the snaffle bit) in the English riding disciplines.
In the horse show world, it is most prevalent in American hunt seat equitation classes, and also occasionally seen used by eventers and show jumpers. It is legal in show hunter, and English pleasure, but not as often seen there.
In the United Kingdom, the pelham is often used in place of a double bridle in show hunter, show hack, Riding Horse, show cob and mountain and moorland classes. The use of pelhams is forbidden, however, in equitation and novice classes.
The pelham is not permitted in dressage at any level. In the horse sport world, the pelham bit is often used in polo. The pelham bit is also occasionally used by young children on hard-pulling ponies, allowing the small riders to keep control without resorting to a snaffle bit with a "sharper" mouthpiece, though for children's small hands, the double rein may raise other difficulties, thus a number of gadgets such as the "bit converter" are sometimes employed.
There are times when the pelham will not work due to the horse's conformation. Horses with a very long interdental space will need the bit placed higher up (to keep it in contact with the corners of the mouth for the snaffle action), which will result in the curb chain tightening too high on the lower jaw. This can be very painful for the horse, and result in bruising.
However, the pelham can be very useful in horses with small mouths, when the action of the double bridle is desired. If a horse's mouth is too small to comfortably hold two bits, a pelham may provide a good alternative.
The pelham is never legal for use in competition in any western riding discipline, where either a snaffle or a curb bit is used, though it is seen occasionally as a training tool to transition a young horse from a snaffle to a curb. In fact, a "cowboy pelham" is a style of loose-jawed curb bit with additional rings at the mouthpiece for a second set of reins to be added.
The angle cheek pelham was formerly used in the Australian Light Horse and other cavalry units as it was designed to suit as many horses' mouths as possible. The Australian design had one side of the mouthpiece smooth and the other serrated. Various rein attachments were also possible with this bit.
[edit] Fitting the Pelham
Pelhams are generally placed lower down in a horse's mouth than snaffle bits, usually just touching the corners of the mouth without creating a wrinkle. The lower the bit is placed, the more severe it is as the bars of the mouth get thinner and so pressure is more concentrated.
The curb chain should be adjusted correctly, lying flat against the chin groove and only coming into action against the jaw when the curb ring is rotated 45 degrees.
