Curb chains can be attached to various types of bits as part of the horse’s riding equipment. The bridle chain attaches to the bit in the horse’s mouth and sits below the horse’s chin groove. It prevents the bit from turning too much and limits the pressure on the upper palate of the horse’s mouth.
Whether using a Western bit such as the Willow Bit, Tom Thumb, or the various corrective bits, or an English bit such as the Kimblewick, Pelham, or double bridle bit, it is important to always use it with a bit chain or strap.
Some driving bits, such as the Liverpool, are curb bits. Many hackamores have a curb bit and should also be used with a curb chain or curb strap. The curb chain or curb strap looks relatively unobtrusive on a bit, but they are important to ensure that the bit is effective and comfortable for the horse.
Bridle chains are often used on bridles and English bits, while leashes are more commonly used on Western bits. However, there are leashes and chains for both parts. A leash, either leather or synthetic, is the softest form of bit. Chains come in different sizes and link thicknesses, and there are many different types of chains available.
Thinner chains can be used for draft horses, but for general riding a medium link leash or chain is sufficient. Whatever the thickness of the chain, it should always be turned so that it lies flat, like a watch band. This may require a few turns to smooth out a tangled chain. On an English bridle, one end of the chain is attached to the right hook of the bit. Once the bridle is on the horse, twist the chain until it is flat and even, then hook it to the left chain. The right hook is usually snapped shut so that the chain does not fall off. There is also a larger center link through which a “lip strap” can be threaded. The lip strap keeps the horse from catching on the bit shanks and prevents the chain from coming off if it becomes unhooked. English leather straps have a pair of chain links at each end of the leather part, so they can be worked as chains.
Unlike the hooks on English chains, Western chains are attached to the bit with a leather strap and buckle on each side. The leather straps have holes in them so that they can be adjusted similarly to a belt. There is no link for a lip strap, as many western bits have a limp or slug bar shank that functions similarly.
A snaffle bit exerts pressure on the bars of the horse’s mouth only when the reins are pulled. However, when pulling on the reins of a bridle bit, the pressure is greater. When the reins are pulled back, the horse feels pressure on the top of the head (the croup), on the bars of the mouth, and in the crease of the chin where the strap or chain sits. The snaffle strap prevents the bit from turning too much in the horse’s mouth, which can be very uncomfortable, especially if there is a large spoon or opening in the mouthpiece of the bit. The rein chain limits the pressure on the upper palate of the horse’s mouth when the bit turns. The pressure under the chin also pulls the bit against the bars of the horse’s mouth, increasing the reining action.
Correct adjustment of the bridle chain is very important. If the bridle chain is too tight, there will be constant and uncomfortable pressure on the horse’s chin groove and bars of the mouth. Rein aids are exaggerated, which can cause the horse to move his head or open his mouth to escape the pressure.
If the chain or strap is too loose or not used, the leverage of the bit will not be as effective. If the bit has an opening or spoon, it can pull hard against the roof of the horse’s mouth and cause pain. The rein strap or chain should be such that the bit shanks do not rotate beyond 45 degrees when the reins are pulled. Many people use the width of two fingers between the horse’s chin slot and the strap or chain to estimate how tight the chain is. This is only an approximation after you verify that the legs turn 45 degrees.
Therefore, always use a belt or chain. It may seem small, but it is an important part of your horse’s bridle.