If your horse's bit is too big, you will find that the bit will move back and forth in your horse's mouth which may hit your horse's teeth. If this occurs, your rein aids will be unclear and will not be transmitted effectively to your horse.
A full cheek snaffle, Pelham or elevator bit should fit snugly next to the horse's cheek, but should not squeeze or pinch. For a loose ring snaffle or any bit with moveable rings, make sure that the horse's lips completely clear the bit ring holes by 1/8 inch on each side.
As a very general guide, you want to have an index finger's clearance.” For loose rings, the horse's lips should clear the bit ring holes by 1/8 inch on each side, to prevent pinching. If you can see half an inch or more, the bit is too big for this horse.
The horse may cross their jaw and totally set against you. They may develop tongue evasion, which means pushing down on the bit, putting the tongue out to the side or over the top, or even snatching and pulling the reins (and your hands) down.
So, it's important that you don't have too much room to start with when the bit is at rest, or with a contact you will end up with too much bit. Too big a bit and you have excessive side to side movement in the mouth, as well as generally being sloppy and uncomfortable in the mouth.
Standard bits are 5 inches wide and are the most common. Pony bits are generally 4 1/2 inches wide, and bits that are designed for Arabians and other light-boned, refined horses are 4 3/4 inches wide.
In horses of any age, bit chewing can signify anxiety. Different horses mature at different rates. Even if your horse seems physically prepared to perform at his current level, he may not be ready mentally. Try reducing the pressure: shorten your schooling sessions, take him on trail rides and so on.
Bits May Inflict Pain
Most riders agree that bits can cause pain to horses. A too-severe bit in the wrong hands, or even a soft one in rough or inexperienced hands, is a well-known cause of rubs, cuts and soreness in a horse's mouth. Dr. Cook's research suggests the damage may go even deeper — to the bone and beyond.
The general rule is; a well-fitting bit will create one or two wrinkles at the corner of the mouth once the bridle is on. If you are still concerned with how your bit fits, you could always ask your equine dentist, veterinarian or your horse trainer for their advice.
An average size for Thoroughbreds is 5 ¼.”
You want to avoid a bit that's too narrow that will pinch the corners of the mouth. The correct width will leave about ¼” of metal extending on each side of the horse's lips.
The mouthpiece of the bit does not rest on the teeth of the horse, but rather rests on the gums or "bars" of the horse's mouth in an interdental space behind the front incisors and in front of the back molars.
Using circles whilst riding transitions can help to bring the horse's inside hind leg more underneath him, which will, in turn, lift his forehand and relieve his reliance for balance on your contact. Another exercise that can be effective in backing a horse off the contact is rein-back.
The bit may be too thick or too wide for that horse's mouth or the horse may have a dental problem. The bit may fit the horse well but be the wrong bit in a particular rider's hands. Horses that have been ridden in draw reins often go behind the bit when the draw reins are taken off. Evasions take various forms.
Most commonly, chokes occur when horses eat concentrated feed too quickly without chewing it appropriately. The feed does not get softened with saliva and forms a firm bolus that gets lodged in the esophagus. However, esophageal obstruction can also occur with hay or straw, hard treats, carrots, or nonfood objects.
Indeed a bit that is too fat for the limited space within the mouth may even impair the horse's ability to breathe and swallow, especially when coupled with hyper flexion (behind the vertical).
1. Head Injuries. Head injuries are by far the most common of all horse-riding-related injuries.
Because horses can not stay off their feet for long periods, broken bones do not have a chance to heal, and so often sadly the kindest way to help a horse with a broken limb is to put it down.
Sometimes a horse will let you know that you have the right or wrong bit in as little as a few minutes, but it often takes a few sessions in a new bit to know for sure.
Trying to get the tongue over the bit is simply an attempt to get away from the bit pressure – the horse is trying to relieve the pressure in its mouth.
The table below scores the severity of each bit, with 1 being the softest and 10 being the most severe.
The softest bits are generally snaffle bits made of rubber. Rubber offers a smooth fit on the bars of the horse's mouth, while the snaffle's rings fit softly in the corners of the horse's mouth without pinching.