Guide to Bits for Horses: Types, Function and Bitless Bridles

Bits are a common component of riding equipment, used by the vast majority of riders. Bits play an important role in communication between the horse and rider, and the choice of bit can influence the horse’s responsiveness to cues.

Horse owners have been using bits since the early domestication of equines. ^[1] Early evidence of bits dates to 3000 BC, although metal bits did not arise until the Bronze Age when smelting became widespread. Today, most riders use bits as a standard piece of riding equipment, although there is growing interest in bitless bridles.

There are a wide variety of bits available, with many configurations of mouthpieces and cheekpieces available. Whether you’re a seasoned rider or a novice equestrian enthusiast, understanding the function and impact of bits is fundamental to ensuring the comfort and performance of your horse.

Read on to learn everything you need to know about bits, including their various types, how they work, and considerations when choosing the right bit for your horse.

How Bits for Horses Work

Bits allow riders to apply pressure to the horse’s mouth and head as a means of control. Horses naturally want to evade pressure, causing the horse to change its way of going in response to a rein cue. ^[1]

When bit pressure is strong, either due to the rider’s hands or mechanics of the bit, horses may respond unfavorably and fight against this pressure. ^[1] These horses may require different bitting choices to find a level of pressure that the horse accepts, while still allowing the rider to communicate effectively. ^[1]

There are two main factors to consider in a bit’s function: its action and severity.

Bit Action

Depending on the sport performed, the horse’s behavior, and other factors, riders select bits based on the location(s) where the bit applies pressure. ^[1] The location where the bit applies pressure is called the bit’s action.

The bit’s action is largely determined by the cheekpieces. ^[1] Depending on this configuration, rein action moving the bit in the horse’s mouth can apply pressure in one or more locations. ^[1]

Common locations for bits to apply pressure include: ^[1]

• Poll
• Tongue
• Lips
• Palate
• Bars
• Chin groove
• Nose

These areas are highly sensitive, with many nerve endings that can detect even subtle changes in bit pressure. ^[1] This allows the horse to detect even small movements of the rider’s hands on the reins.

Bit Severity

Riders must also consider the severity of a bit when making bitting decisions. The bit’s severity depends on the degree of pressure applied, and the pain associated with pressure.

The degree of pressure depends on the bit’s action and the configuration of the bit. For example, snaffle bits, where the rein attaches directly to the bit’s mouthpiece, typically have a 1:1 ratio of pressure. ^[1] In other words, the amount of pressure put on the reins is the amount of pressure felt in the horse’s mouth.

This contrasts with leverage bits and other types of bits, which have shanks. ^[1] In these bits, the reins attach lower on the shanks than the mouthpiece. This produces a leverage effect that acts on the horse’s mouth and poll.

These bits increase pressure coming from the rider’s hand due to the leverage effect. ^[1] For example, a leverage bit with a 3-inch shank could increase the pressure felt by the horse by a 1:3 ratio. ^[1]

The mouthpiece of the bit also affects its severity. Some mouthpieces have a “sharper” effect on the horse’s mouth, versus others which produce dull pressure. The “sharper” the mouthpiece, the more severe the bit, regardless of the bit’s action or configuration. ^[1]

Finally, other bit attachments can also affect bit severity. For example, some bits have curb straps which sit in the horse’s chin groove and apply pressure when the rider activates the bit.

Curb straps range in severity from a simple piece of leather to a chain. A leather strap produces duller pressure, while the chain produces a sharper, more severe pressure. ^[1] This also applies to bits with built-in nosebands that can also vary in severity depending on design and tightness..

The bit’s severity can disguise gaps and flaws in the horse and rider’s training. ^[1] It’s important that riders do not rely on a stronger bit to fix problems encountered during their training process. ^[1] All riders should aim to ride in the gentlest bit possible for their horse, to maximize welfare.

Mouthpieces

The mouthpiece is the part of the bit that sits in the horse’s mouth. Mouthpieces come in many different designs and materials. Riders choose the material, size of the bit, and the mouthpiece design based on their horse’s individual needs as a performance animal. ^[1]

Materials

The bit’s material can affect the horse’s response to the bit. Some horses prefer the taste of certain metals over others, while some horses cannot tolerate metal bits whatsoever. Often, a degree of experimentation is necessary for riders to determine what bit material works best for their horse.

Common mouthpiece materials include: ^[1][2]

• Stainless steel: The conventional material for making bits
• Copper: Promotes increased salivation in horses
• Sweet iron: A sweet-tasting metal that promotes increased salivation in horses
• German silver: A gold-colored metal that tastes sweeter than regular stainless steel
• Rubber or plastic: Provides a softer feel for the horse’s mouth
• Leather: Provides a soft feel and conforms to the shape of the horse’s mouth when wet

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Sizing a Bit

Riders must choose bits appropriate for their individual horse, based on the horse’s conformation. ^[1] The horse must find the bit comfortable to wear at rest, when the rider is not applying any rein action.

Factors of the horse’s conformation to consider when sizing a bit include: ^[1]

• Width of the horse’s mouth
• Size of the horse’s tongue
• Available space between the horse’s tongue and their palate

Tack suppliers usually only list the width of the bit’s mouthpiece on the store tag. ^[1] Riders should have an experienced person examine the bit’s fit in the horse’s mouth. This includes evaluating for: ^[1]

• Pinching of the tongue
• Assessing the thickness of the bit relative to the horse’s mouth
• Ensuring the bit does not interact with the horse’s palate unintentionally

The thickness of the mouthpiece also impacts severity. ^[6] Thinner mouthpieces produce sharper pressure, while wider mouthpieces produce a dull pressure. However, a mouthpiece that is too thick can cause the bit to sit uncomfortably in the horse’s mouth. ^[6] Most mouthpieces are around 9.5 mm (3/8 inch) in diameter. ^[6]

Professional bit fitters, called loriners, can help riders find the ideal fit for their horse. ^[3]

Mouthpiece Design

There are many different mouthpieces available for riders to choose from. The design of the mouthpiece can vastly impact the severity of the bit, so choosing the right mouthpiece for your horse is an important part of the bitting process.

Mouthpiece designs vary based on the mouthpiece configuration, mullen (arc or shape), and the style of the bit’s bars (the parts that sit against the horse’s tongue and mandible). ^[4]

Mouthpiece Configurations

In general, mouthpiece configurations are either jointed or ported. Both designs allow more room for the horse’s tongue. Jointed designs are more common in English riding, while ported designs are more common in Western. ^[1]

Joints refer to connections between separate pieces of metal within the horse’s mouth. This increases the flexibility of the bit, allowing it to conform to the horse’s mouth shape.

Common non-ported configurations include: ^[1]

• Mullen mouth or straight bar: A straight bar of material with no joints. Some horses resist these bits as they do not mold to the shape of their mouth
• Single-jointed: Two straight bars with a single joint between them. This type of mouthpiece can have a nutcracker effect when rein pressure is applied and may poke the horse’s palate unintentionally
• Double-jointed: These bits have two bars connected by a smaller center link, making 3 segments in total. These bits tend to conform to the shape of the horse’s mouth and tongue better than Mullen mouths or single-jointed bits. Double-jointed bits can have a variety of center links, including roller balls, dog bones, rings, flat discs or lozenges. These center links have a variety of effects from increasing salivation to increasing the severity of the bit
• Waterford: This mouthpiece is entirely links of metal, somewhat resembling a chain. This mouthpiece has extreme flexibility and can prevent the horse from “leaning” on the bit

Ported bits usually have no joints, but rather an upward swoop in the center (the “port“) to allow more room for the horse’s tongue or to apply pressure to the horse’s palate. ^[5] Ensuring the shape of the port matches the horse’s tongue conformation is an important consideration when fitting these bits.

The design of some ports increases the severity of the bit by acting on the horse’s palate when the rider activates the reins. ^[1] The port must be 5 – 6 cm (2 – 2.5 in) high to contact the palate in most horses. ^[6]

Common port configurations include: ^[1]

• Basic port: These ports are smooth metal. Riders select the style of port based on their horse’s tongue shape
• Segundo: These are ported bits where the sides of the port have small projections that act on the horse’s tongue, increasing bit severity
• Correction port: A ported bit with a very high port, so that when the rider engages the reins the port touches the horse’s palate
• Spoon mouth: The metal of the port flattens instead of maintaining the rounded shape of the rest of the mouthpiece. Usually designed so that the port acts on the horse’s palate
• Spade: These bits are typically a straight metal mouthpiece without a traditional port. Instead, a straight projection from the mouthpiece resembling the head of a spoon sits along the horse’s tongue. Copper-covered braces support the spade and add additional width to the mouthpiece. When the rider activates the bit, the spade applies pressure to the horse’s palate

Some bits have overlap between the two types. For example, some bits have a port with joints on either side, allowing the two sides of the bit to move independently. ^[1]

Mouthpiece Mullen

The “arc” or mullen of the mouthpiece when viewed from the top down can affect the bit’s severity.

Adding a mullen to the bit’s shape makes it more comfortable for the horse, as it matches the curved shape produced by the tongue sitting in the lower jaw. ^[1] Many bit designers add a slight mullen to all their bits to improve comfort. A mullen also ensures that pressure on the bit distributes equally between the tongue and lower jaw. ^[1]

Some riders may choose a straight bar, without a mullen, to increase the severity of the bit’s action. These bits typically have a stronger action on the horse’s tongue, as activating the bit first puts pressure on the horse’s tongue before it contacts the horse’s jaw. Some horses resist this additional tongue pressure and cannot tolerate bits without a mullen.

Bar Styles

The style of the bit’s bars affects the severity of the its action on the mouth. Most bits have smooth bars that produce a dull pressure in the horse’s mouth. Some riders may choose a bar style with a sharper effect.

Common bar styles for bits include: ^[1]

• Smooth: The bars are smooth metal with no edges
• Twisted: These bits have a “twist” along the bars that produces a rough surface. There are slow twists, which have a subtle roughening, and fast twists, which have more prominent roughening. Fast twist bits are more severe than slow twist
• Wire: Twisted wire makes up the bars of these bits. Some have two sets of twisted wires making up each bar
• Magennis: The bars of these bits have a textured surface that can roll, aiming to encourage the horse to play with the bit and increase salivation

The shape of the bars can also affect severity. Most mouthpieces have a round or oval shape to avoid sharp edges that may hurt the horse’s mouth. However, some bits have a triangular or square shape with dulled edges. These bits have a higher severity, as the dulled edges act on the horse’s mouth to produce sharp pressure.

Cheekpieces

The cheekpieces of the bit determine its action, or how and where it applies pressure to the horse’s head.

There are four main classes of bits based on their action: ^[1][3][7]

• Snaffles: Allow direct contact with the horse’s mouth
• Leverage bits: Act on the horse’s mouth, poll, and chin groove
• Gag bits: Act on the horse’s mouth and poll
• Bitless bridles: “Bits” that have no mouthpiece and act on the horse’s poll, nose, chin groove, and/or cheeks

Snaffles

Snaffles are direct action bits, meaning the amount of pressure applied to the reins is the same as the pressure on the horse’s head. ^[1] All snaffles have the rein attachment point directly in line with the horse’s mouthpiece. ^[1][5]

Different types of snaffles have different “rings” (bit and bridle attachment sites on either side of the mouthpiece). ^[1][5] The type of rings can affect how the horse responds to the snaffle, but do not change the snaffle’s action.

Common snaffle types include: ^[1][8]

• D-ring: These snaffles have D-shaped rings attached by hinges to the mouthpiece. They also have no sliding of the ring when the reins engage. This bit is good for younger horses who need a steadier signal from their rider
• Eggbutt: Have egg-shaped rings on either side, and attach to the mouthpiece by a hinge. The rings can move horizontally, but do not slide when the reins engage. This bit is good for younger horses who need a steadier signal from their rider
• Loose rings: The rings of these snaffles run through holes in the mouthpiece and are not fixed in place. When rider engages the bit, the rings slide slightly, giving the horse a “pre-signal” that bit pressure is about to occur
• Full cheek: Have a small ring attached to the mouthpiece by a hinge. At the junction between the mouthpiece and cheek, there are long metal projections extending from both the top and bottom of the bit (the “full cheek”). These projections can help horses learn to steer by applying pressure on the side of their nose that guides them to follow the bit
• Fulmer: A type of full cheek where the bit rings are loose rather than fixed. It offers “pre-signal” to the horse while also helping steer them
• Baucher: Also called a hanging cheek or Fillis. These bits have a short extension off the main ring that riders attach the bridle to. Bauchers may provide a small degree of leverage, however this is controversial among bit experts

Leverage Bits

Leverage bits act on the horse’s mouth, poll, nose and chin groove, depending on their design. To act on the chin groove, leverage bits must have a curb strap. ^[1]

The curb strap engages when the shanks rotate, putting pressure on the chin groove and producing a vice-like pressure between the horse’s mouth and the chin strap. Since the chin strap pulls the bit down against the horse’s tongue and jaw, the horse turns their head inwards to seek relief from the bit’s pressure. In combination with poll pressure, this typically encourages the horse to lower their head and tuck their chin towards their chest.

The curb strap also prevents shanks from over-rotating, which can cause the bit to rise in the horse’s mouth and put pressure on the lips at the corner of the mouth. Some riders do not use curb straps on their leverage bits, which gives them more of a gag action. To act on the nose, leverage bits must have an attached noseband.

Leverage bits are recognizable due to their long sides. The portion of the cheekpiece above the mouthpiece is called the purchase, and the portion below the mouthpiece is called the shank. ^[1]

The rider’s reins attach to the bottom of the shank, and when the rider engages the bit, it rotates in the horse’s mouth. ^[1] This brings the purchase, attached to the horse’s bridle, forward, pulling down on the cheekpieces of the bridle and increasing poll pressure. ^[1][5]

The relative lengths of the purchase and the shank determine the degree of leverage, and therefore the severity of the bit. ^[1][2] Longer shanks require less rein pressure to signal the horse. ^[1]

The shape of the shank can also impact the amount of leverage. English bits usually have straight shanks, which tend to have higher leverage. ^[1] However, riders typically use a snaffle rein with English leverage bits as their primary source of communication with the horse, and only engage the leverage action when necessary. ^[1]

English Bits

The three most common English leverage bits are: ^[1][3]

• Pelham: This bit has a fixed snaffle ring attached to the mouthpiece, a short purchase, and a short shank, all combined into one bit. Riders use one rein on the snaffle rings and another on the shank rings to control the horse. Some riders may use a rein converter, allowing them to engage both the snaffle and shank action with only one rein, strengthening the pressure applied by the bit
• Weymouth: This is a traditional curb bit with no snaffle ring, only a purchase and shank. English riders use these bits at the same time as a snaffle bit in a configuration called a double bridle, which is commonly used in dressage and required at the upper levels
• Kimberwicke: This bit is a combination between a snaffle and a leverage bit. The cheekpieces have a D-ring snaffle shape, however there is a curb strap and a short purchase. Riders can use these bits with one or two reins. If using one rein, riders can select a lower or higher attachment to influence the strength of the bit. When the rider activates the bit, it has a primarily snaffle action, with a small amount of leverage on the poll and chin groove

Western Bits

Western curbs are designed for riding with minimal contact with the horse’s mouth, in contrast to English riding where consistent contact is desirable. ^[1] Therefore, Western curbs have no snaffle action, and rely solely on applying leverage when necessary. ^[1]

Common Western shank shapes include: ^[1]

• Curved grazer shanks: This is the most common type of shank. The shanks gently curve towards the rider, minimizing some of the leverage compared to a straight shank. They also keep the shanks out of the horse’s way when grazing
• S-shaped: S-shaped shanks help soften the leverage and keep the shanks away from the horse’s mouth
• 7-shaped: 7-shaped shanks also diffuse leverage on the poll and chin groove, however have slightly stronger leverage than S-shaped shanks due to the straightness of the shank

Gag Bits

Gag bits act only on the mouth and poll. ^[1] Since there is no curb strap, there is no signal to the horse to turn their head inwards after poll pressure encourages them to put their head down. ^[1] Therefore, horses respond only by lowering their head rather than tucking their chin.

Since there is no curb strap to prevent over-rotation and  hold the bit in place, gag bits also tend to apply more pressure to the lips at the corner of the horse’s mouth rather than their tongue or lower jaw. ^[1] This upward pressure may signal to the horse to raise their head, directly counteracting the head-lowering cue from the poll pressure. ^[1]

For this reason, many experts believe gag bits give horses conflicting signals and trigger conflict behaviors in horses, and therefore should not be used. ^[1][9]

Riders may choose to ride in gag bits using one or two reins. Using two reins allows riders to control when and how the gag action is engaged along with conventional pressure on the mouthpiece. When one rein is used, the gag action is always engaged when rein pressure is applied.

The most common types of gag bits are: ^[1]

• Conventional, draw or running gag: This bit has rope that runs from the bridle, slides through spaces in the rings of a snaffle bit, then attaches to the reins. This gives a “draw action” when the rider pulls on the reins, resulting in the rope sliding through the bit and pulling on the horse’s poll and lips. These bits are most common in English disciplines, particularly for show jumping, but are also seen in Western disciplines such as barrel racing
• Wonder gag: This bit looks like a loose ring snaffle with a purchase and shanks. When the rider pulls on the reins, the rings of the bit slide through the mouthpiece, activating the lips and the horse’s poll. These gags are most common in Western riding
• Elevators: These bits are similar to a Pelham, but have a long purchase and usually longer shanks. Although the mouthpiece is fixed, the long purchase means the horse’s lips engage before poll pressure is applied in a “pseudo-gag” action. Elevator bits may have one or two rings on the shanks, allowing riders to control the strength of the gag action
• Dutch gag: Also called a four-ring or bubble bit. These bits look like a loose ring snaffle with additional rings welded to the top and bottom of the loose ring. The bridle attaches to the very top ring, then reins attach to one of the bottom rings, producing leverage. Since the loose ring slides and there is no curb strap, this produces the gag action

Elevator bits may have one or two rings on the shanks, allowing riders to control the strength of the gag action

Bitless Bridles

Many riders now choose to use bitless bridles instead of a traditional bit. These bridles work by applying pressure on various parts of the head, making no contact with the mouth. ^[1] Horses that do not tolerate bits tend to do well wearing a bitless bridle. ^[1]

There are many types of bitless bridles, and new designs continue to emerge. Common designs currently used include: ^[1]

• Bosal hackamore: These bridles are most common in Western riding. They have a bosal, a braided rawhide noseband, that attaches to the rider’s reins. Pressure is applied on the top and sides of the nose to stop and steer. Bosal hackamores were developed from traditional Spanish training methods used by vaqueros.
• Mechanical hackamore: These hackamores have a rope, metal, or leather noseband attached to long shanks that the rider’s reins attach to.  These shanks can be longer or shorter, depending on design. They usually have a curb strap as well to apply pressure to the chin groove and prevent over-rotation.
• Wheel or butterfly hackamore: These hackamores have spoked wheels on either side of the horse’s head rather than long shanks. Pulling on the reins rotates the wheels slightly, applying nose, chin groove, and poll pressure.
• Rope halters: Some riders choose to ride in rope halters rather than using a separate piece of equipment. These halters apply pressure on the horse’s head by rope knots over the horse’s nose. Four-knot rope halters create more intense pressure than two-knot halters due to the placement of the additional knots over sensitive facial nerves.
• Sidepulls: Work similar to a halter, with the reins attached to the sides of the horse’s noseband. Pressure is applied to the top and sides of the nose in order to stop and steer.
• Cross-under sidepulls: These sidepulls have additional leather straps that run under the horse’s jaw in an “x” shape and attach to the far side of the head. These straps attach to the reins, creating additional guiding action on the side of the face when giving rein cues.

Equipment and Management

Choosing the bit worn by your horse is an important decision that can directly impact safety, comfort, welfare, and performance.

The choice of bit depends on several factors: ^[1]

• The horse’s current training level
• Existing training issues such as heavy on the bridle, too forward, head tossing, etc.
• Your discipline, including any sport-specific rules
• Your riding ability
• The advice of experts working with you and your horse

Selecting a bit can require trial-and-error, and your choice of bit may change as you and your horse’s training or sport needs evolve over time.

Work with qualified professionals, such as trainers and bit fitters, to ensure that your chosen bit is suitable for your specific horse and legal for the discipline you compete in.

Other considerations in overall horse performance include nutrition, veterinary care, farriery, training program development, and exercise conditioning. Integrating professionals from these fields into your horse’s care program can help improve performance and overall horse health.

Want to know if your horse’s diet is missing anything? Submit their information online for a free evaluation and consult with our expert equine nutritionists to develop the best feeding plan for your team.