How to Choose the Right Bit for Your Horse

In our articles and conversations with customers, we devote a lot of attention to choosing the right bridle, finding the correct size and adjusting it for a proper fit. As a saddlery workshop specialising in handmade leather tack, these are the areas where we particularly want to help our customers make informed decisions. However, if you use a bit, choosing the right one is just as important to ensure that your horse is as comfortable as possible in its new bridle.

Choosing the right bit for your horse can be divided into two stages: selecting the type of bit and choosing the correct size. Besides its length, a bit also has a certain thickness. It is commonly believed that the thicker the bit, the milder it is. To some extent, this is true, but it is not the whole picture.

The distance between the mandibular bars of the upper and lower jaws varies from horse to horse. A bit should not put pressure on the jaws when the mouth is in a neutral position. If the bit is too thick for the horse, it constantly presses against the jaws. This can be extremely painful, especially if the noseband prevents the horse from opening its mouth.

Therefore, a bit that is too thick can be just as uncomfortable and painful as one that is too thin. How can you determine which range of bit thicknesses will be comfortable for your horse?

There is a simple test that, while fairly general and not particularly precise, can give you a basic idea of the appropriate bit thickness for your horse. It is also easy to perform without any additional tools. Place your index and middle fingers together and insert them into the horse’s mouth where the bit normally sits.

• If you feel pressure on both fingers (indicating a small gap between the upper and lower jaws), a thinner bit of 14–16 mm is recommended.
• If you feel no pressure, a thicker bit of 16–18 mm may be suitable.

The Best Bit Size For Your Horse

To measure the correct bit length for your horse, you can use either specialised measuring tools, which are commonly available from breeders and professional bit fitters, or simply a piece of soft rope and a measuring tape.

• Pass the rope through your horse’s mouth where the bit would normally sit. A correctly fitted bit should create one small wrinkle at each corner of the mouth. Make sure the rope is thick and soft enough to avoid injuring your horse.
• Hold the rope at both points where it meets the corners of the horse’s mouth.
• Remove the rope while keeping hold of these points, then lay it against a measuring tape to determine the length.
• Add another 1 cm to the measurement — allowing 0.5 cm between the corner of the mouth and the snaffle ring on each side. This will give you the required bit size.

However, there are some important differences depending on the type of bit.

Loose-ring snaffles should have approximately 0.5–1 cm of space between the corner of the horse’s mouth and the bit ring on each side. The bit should not be too narrow, as the rotating rings could pinch the corners of the mouth.

Bits with fixed cheekpieces, which include most other designs, should fit more closely against the corners of the mouth. A gap of approximately 0.5 cm should be comfortable for the horse.

When choosing bits for a double bridle, pay attention to the shape of your horse’s jaw.

Every horse’s jaw becomes narrower towards the nose, but this narrowing is more pronounced in some horses than in others. As a result, the curb bit, which sits below the bradoon, may need to be 0.5–1 cm shorter than the bradoon.

Choosing a Bit: Single-Jointed or Double-Jointed?

When rein pressure is applied, a single-jointed mouthpiece puts pressure on the bars of the jaw, the edges of the tongue and, under strong rein tension, the roof of the mouth. This squeezing action can cause considerable pain. Therefore, contrary to popular belief, single-jointed bits are not necessarily mild and are poorly suited to many horses. They are also particularly unsuitable for inexperienced riders or riders with harsh hands.

It is important to consider not only the squeezing action on the jaws but also the pressure on the palate. If the rider jerks or pulls strongly on the reins, the joint of the mouthpiece can press forcefully against the roof of the horse’s mouth, potentially causing significant injury.

A standard single-jointed mouthpiece has a particular manufacturing characteristic: one side of the mouthpiece is longer than the other. This can result in stronger pressure on one side of the jaw. Some riders use this effect to gain greater control over a horse that resists contact on one rein.

However, while this approach may help address the symptom, it does not solve the underlying problem. Resistance to one rein is often caused by asymmetry or crookedness in the horse and should be addressed through correct straightening exercises.

A double-jointed mouthpiece distributes rein pressure more evenly over a larger area of the tongue without putting the same direct pressure on the sensitive palate. It is important to understand that a thick central link can place considerable pressure on the horse’s tongue and, if the bit is too thick, on the palate as well. A mouthpiece with a central link angled forward at approximately 45 degrees generally rests more comfortably on the horse’s tongue.

Mullen Mouth Horse Bits

A Mullen mouth bit has a solid mouthpiece without joints. Straight, rigid Mullen mouthpieces distribute pressure evenly across the tongue. Compared with jointed bits, straight mouthpieces place less concentrated pressure on the edges of the tongue and the bars of the jaw. The stronger the rein tension, the greater the pressure applied to the tongue and lower jaw.

Unlike bits that also exert leverage pressure on the poll, such as Pelham bits, a solid mouthpiece can be used for horses that tend to evade contact by coming behind the bit or leaning heavily on it.

A solid mouthpiece can also be flexible. These mouthpieces are made from firm rubber or incorporate a flexible rubber section. When rein pressure is applied, the pressure is distributed across the tongue but increases towards its edges. Flexible solid mouthpieces are often well accepted by horses that do not respond comfortably to jointed bits.

Solid Mouthpieces Horse Bits with a Port

Compared with a straight Mullen mouthpiece, a ported mouthpiece reduces pressure on the tongue and transfers more of it to the bars of the jaw. Unlike jointed bits, it distributes pressure over a larger area of the bars rather than concentrating it near their edges. The port can be high or low.

The higher the port, the greater its potential to exert pressure on the roof of the mouth. A low port does not normally create this type of pressure.

What Bit Material to Choose for Your Horse?

Metal Alloys Horse Bits

The greatest advantages of metal alloys are their strength and long service life. There are significant functional differences between the various metals used in horse bits.

Copper alloys, for example, are very popular materials for mouthpieces. Copper is considered a good material because its natural oxidation process produces a slightly sweet taste and encourages the horse to chew the bit. Since pure copper is relatively soft, it is usually combined with other metals.

Copper-aluminium alloys are particularly strong. Aluminium strengthens the copper but also largely prevents its natural oxidation process. As a result, inexpensive copper alloys do not necessarily have a significant effect on salivation. Not every horse likes the taste of copper, and the only way to find out whether your horse accepts it is through your own experience.

Stainless Steel Bits

Stainless steel has a neutral taste and does not have properties that actively encourage salivation. If your horse dislikes the taste of copper, stainless steel may be a good alternative.

Stainless steel bits are very strong and durable. They are also usually less expensive than equivalent models made from copper alloys. Price is another factor to consider when choosing a bit. It is important to be realistic about which price range you can comfortably afford.

Rubber and Plastic Bits

Compared with metal bits, plastic and rubber mouthpieces are softer. They usually contain an internal metal core to prevent the horse from biting through or damaging the mouthpiece. Another advantage is that these bits are more comfortable for horses in freezing temperatures. Not all horses like the taste of rubber, but soft, flexible plastic mouthpieces are generally well accepted.

Choosing the right bit is not always straightforward. You will most likely need to try several different options before finding the one that suits your horse best. The right combination of a properly fitted bit and bridle will help keep your horse comfortable, support its health and contribute to a long, healthy working life. And to find a bridle with the perfect design and fit for your horse, explore our custom-made bridles, handcrafted to order at the Lazypony saddlery workshop.