An alarming number of equestrians—across all varieties of riding levels and disciplines—aren’t aware of the mechanics behind the tack they use on their horse(s). Even more concerning is that many who believe they are educated on their equipment are often misled by the brands they bought their equipment from and should be able to trust. Starting with bits, I’d like to bring what I know to the discussion table. Anyone can call themselves a professional and plenty of loopholes exist in our industry, unfortunately, this means many greedy people won’t hesitate to show you a flashy shortcutting tool designed to suppress a horse’s behavior through discomfort or pain while claiming it a miracle worker.

This is why it’s so important to thoroughly check who you choose to learn from, especially regarding tack. What’s the goal behind them taking the time to share what they know with you? Is it a transactional motive, or are they truly passionate about what they do? In making this document, I aim to share the raw mechanics of the bits available to riders and their horses, highlight common marketing flaws in biomechanically unfair bits that are advertised as “problem solvers,” and simply make this choice easier for you. After all, everyone’s two cents is what makes someone their fortune.

Enjoy!

SNAFFLES AND LEVERAGE BITS

There are two main styles of bits: snaffles and leverage bits. Snaffles operate on a 1:1 ratio, meaning that the amount of pressure the horse feels in its mouth directly corresponds to the amount of pressure the rider applies to the rein. For example, if you pull with one ounce of force, the horse experiences exactly one ounce of pressure in its mouth. Unlike snaffles, leverage bits have an amplified ratio. This means that for each ounce of force you apply to the rein, the horse feels more than one ounce of pressure, with the exact amount depending on the design of the leverage bit. All bits have a cheekpiece where the headstall and reins are connected, and a mouthpiece which is placed in the horses’ mouth.

Above is an example of a snaffle bit. The word “snaffle” comes from the Old Frisian word “snavel,” meaning mouth. The rings on either side of the mouthpiece form the entire cheekpiece, with the headstall and reins attached to these rings. When the reins are pulled on a snaffle bit, the horse feels pressure primarily in its mouth. However, due to the headstall helping hold the bit in place, the horse also experiences slight pressure on its poll (the joint between the skull and the C1 vertebrae) even though snaffles aren’t necessarily designed to work off poll pressure. Poll pressure is used to cue the horse to lower its head.

Above is an example of a leverage bit. They are called leverage bits due to the cheekpiece working as a lever, amplifying the pressure. When the reins are pulled on a leverage bit, the horse will feel pressure on its poll and in its mouth. However, because all leverage bits require a curb strap to prevent the bit from over-rotating, the horse will also feel pressure surrounding its chin groove.

Before we start, here is an explanation of some basic terminology you may have heard!

Direct pressure: engaging the bit on the side you're turning toward to cue the horse
Indirect pressure: engaging the bit opposite to the side you’re turning toward to cue the horse
Neck reining: Not making any contact with the bit itself (constant slack), shifting the weight of the reins to cue the horse

TYPES OF MOUTHPIECES

Mullen

A mullen mouthpiece is a mouthpiece with no joints. They engage mostly on the top of the tongue and are great for horses who struggle to hold the bit properly, as the lack of movement creates better stability in the mouth, allowing the horse to hold the bit more easily.

Single-Joint

A single-jointed mouthpiece has two cannons that make up the mouthpiece, with a joint in the middle to connect the cannons. This allows you to cue the left or right side of the mouth depending on which rein you engage. Single-jointed mouthpieces engage mostly on the bars of the mouth and the sides of the tongue.

Double-Joint

A double-jointed mouthpiece has two cannons on either side of the center link, with two joints connecting the cannons. Similar to a single-joint, a double-jointed mouthpiece allows you to cue the left or right side of the mouth independently and engages on the bars of the mouth and tongue. However, a double-jointed bit also engages on the top of the tongue instead of just the sides. The center link must be smooth and rounded to prevent discomfort caused by concentrated pressure on the tongue.

When choosing a double-jointed mouthpiece for your horse, it’s important to be mindful of center links that rest or engage at an angle. For example, below you will see 4 different examples of center links.

On the left are two different lozenges, as long as the link or joints aren’t bulky, these are fantastic options.

Photo Credit: Simay Akın-Üreten

On the right is a French link (top) and a Dr. Bristol (bottom). Both of these center links are designed to sit and engage at an angle, creating concentrated pressure on the tongue whenever the horse attempts to carry the bit properly, with the pressure intensifying when the bit is engaged. Concentrated pressure causes a bit to work off of discomfort, not communication.

Photo Credit: Simay Akın-Üreten

Barrel-Swivel

A barrel-swivel mouthpiece has two cannons on either side of a barrel-shaped swivel center link. While this is technically a double-jointed mouthpiece, the barrel swivel prevents the mouthpiece from pinching or collapsing around the jaw when engaged.

Multi-Joint

Waterford mouthpieces in the English world and chain mouthpieces in the Western world are the most common multi-jointed mouthpieces. The idea behind them is to prevent bracing and also fit hard-to-fit horses. However, bracing is a training issue, and the more joints a mouthpiece has, the less stable and more pinching it becomes in the mouth. Multi-jointed mouthpieces are also constantly in motion when the horse is moving, making it increasingly difficult for a horse to carry the bit.

Additional Considerations for Mouthpieces

The cannons of all mouthpieces must be curved to accommodate the horse's oral cavity. If a mullen mouthpiece isn’t properly curved, the outer half of the mouthpiece will press the roof of the mouth and the corners of the lips upward when one rein is engaged, which confuses the horse. If the cannons of a single-jointed mouthpiece are not adequately curved, the mouthpiece will form a ‘V’ and constantly press on the sides of the tongue and the roof of the mouth. This is also referred to as a ‘nutcracker.’ For a double-jointed mouthpiece, if the cannons aren’t curved appropriately, the joints of the mouthpiece end up digging into the sides of the tongue. The curvature of the cannons is one of the most important factors in bit fit, however, it's often overlooked due to being such a physically small difference. Below you’ll see an example of two single-jointed mouthpieces, one with what would be considered a ‘V-break,’ and the other a ‘U-break.’ Keep in mind the bit needs to curve adequately to accommodate the tongue.

All mouthpieces need to be smooth for a horse to comfortably carry a bit. Some bits are made with square, cherry roller, twisted wire, corkscrew, mule-mouth, or similar mouthpieces, and are advertised for ‘stronger horses’. These mouthpieces are designed to cause pain whenever the bit is engaged, with the goal of overpowering the horse. Due to the uncomfortable nature of these ridged mouthpieces, horses are unable to hold these bits properly and will resort to letting them hang in their mouth. As a result, the mouthpiece ends up banging around in the horse’s mouth.

Rollers and Crickets are a great option for particularly mouthy horses. These are essentially fidget toys for horses who like playing with their bit or get bored or anxious while waiting their turn at events. While both are very similar to one another, the major difference is that rollers are very quiet, while crickets also give you a verbal signal if your horse is licking and chewing.

Horses with large tongues often benefit from ported bits. Ports allow more room for the tongue to rest under the mouthpiece. When buying a ported bit for your horse, it’s important to steer clear of abrupt ports, like correction ports. These mouthpieces have either a ninety-degree or nearly ninety-degree bend, creating a crushing action on the tongue when engaged. Bits with abrupt ports, like some segundas, can have hooks on the inside of the port that amplify the pain from the crushing action as they dig even more into the tongue when the bit is engaged. Below are examples of two abrupt ports (top photos) and two well-designed ports (bottom photos). From left to right, the abrupt ports are a correction port and a segunda, and the well-designed ports are a ported mullen and a ported barrel swivel.

Do you know how many materials are used to make mouthpieces? Or the functions behind them all? Here is a quick list of the most common materials used for mouthpieces, as well as their functions:

Stainless Steel - Doesn’t rust, can reduce salivation
Sweet Iron - Designed to rust, promotes salivation
Copper - Doesn’t rust, promotes salivation
Leather - Doesn’t rust, conforms to a horse's oral anatomy, and provides softer cues
Rubber - Doesn’t rust, physically softer than metal, but harder than leather
Gel - Doesn’t rust, a slightly softer and improved version of rubber

**Keep in mind saliva is lubrication for the mouth. A well-lubricated mouth is ready for bit cues!

CHEEKPIECES PART ONE - SNAFFLES

O/Loose Ring

Loose-ring cheekpieces allow the rider to use more subtle cues with their bit. The ring moves as the rider takes the slack out of the rein, giving the horse time to respond to the signal and prepare their feet before contact is made with the mouth. The larger the ring, the more time the horse has to respond to the pre-signal before the rider fully engages the bit. Larger rings also help with steering. When engaging the inside rein, the outside ring pushes against the face (and vice versa), further guiding the horse in the right direction.

Fixed Ring

Fixed-ring cheekpieces allow the rider to give more immediate cues. Although the horse can still feel the slack in the rein being picked up, the cheekpiece is fixed in place, resulting in much less pre-signal before contact is made with the mouth.

Dee Ring

Dee-ring cheekpieces are a type of fixed-ring cheekpiece. The larger, D-shaped rings nudge the outer side of the face when the inner rein is pulled, which can help with steering.

Full Cheek

Full-cheek cheekpieces are another type of fixed-ring cheekpiece. They are the ultimate steering aid, as the prongs above and below the ring fully guide the horse in the direction you want to turn. These prongs also prevent the bit from being pulled through the mouth. Full cheek bits need to be used with bit keepers, which are small leather tabs hooked through the upper prong and attached to the headstall. Without bit keepers, the weight of the prong causes the bit to tilt forward in the mouth, interfering with the bit cue.

Fulmer

Fulmer cheekpieces are a combination of loose-rings and full-cheeks. They provide the steering aid of a full-cheek and the pre-signal of a loose-ring.

Half Cheek

Half-cheek cheekpieces are like a full-cheek bit with only the lower prong. They are a common choice for racing and driving horses. You do not need bit keepers with a half cheek. Below is an example of a half-cheek cheekpiece with a ring, they do not always have one.

Baucher

Baucher cheekpieces are the only snaffle that eliminates poll pressure. This is the only cheekpiece that has a purchase but no shank, meaning there is no leverage and, therefore no need for a curb strap. When the rein is engaged, the purchase lifts off of the cheekpiece, preventing the crown of the bridle from pressing on the poll when the rider pulls the bit.

Wilson
Wilson cheekpieces have four rings instead of two. Traditionally used as a driving bit, these snaffles are designed to have the headstall attached to the inner two rings and the reins attached to the outer two. The idea is that the rings push on a larger area of the face when steering, however when these cheekpieces are paired with any variety of jointed mouthpieces, the inner rings can squeeze the sides of the face, creating discomfort. Therefore, it’s important to only pair a Wilson cheekpiece with a mullen mouthpiece.

CHEEKPIECES PART TWO - LEVERAGE

Pelham

Pelham cheekpieces are used with two reins. The upper ring functions as a Baucher, while the lower ring provides leverage. Straight shanks on a leverage bit mean that the leverage will reach its full potential of pressure more quickly than it would with swept-back shanks. Pelhams come in a few styles, here’s a quick explanation of each type!

Baby Pelham: Typically two-inch (5cm) shanks, providing less leverage but being more abrupt as it takes less time for the shank to engage fully

Standard Pelham: Typically four-inches (10cm), providing more leverage but being slightly less abrupt as it takes more time for the shank to engage fully

Show Pelham: Same four-inch shank as a standard pelham, however, show pelhams feature a loose-ring Baucher

Swales Pelham

Swales Pelham cheekpieces are a combination of Wilson snaffles and normal pelhams. Each swales pelham has two rings on the inside, with the shanks positioned where the outside rings of a Wilson snaffle would go. Since the shanks are not attached to the rings where the headstall attaches to the bit, this makes swales pelhams the only leverage bit without poll pressure.

Kimberwick

Kimberwick cheekpieces are used with one rein, however, the rider can determine the amount of leverage based on how high or low they hold the rein. The lower the rein is held, the more leverage there is.

A lot of people mistakenly believe that kimberwicks won’t have leverage due to not having a smaller designated rein slot, and believe it would work similarly to a baucher. If you compare a kimberwick and a baucher, you’ll see that the mouthpiece is fixed much lower on a baucher than it is on any kimberwick. For a bit to have leverage, it needs to have a purchase above the mouthpiece, and a way to keep the rein believe the mouthpiece. Bauchers have mouthpieces that are fixed much lower on the cheekpiece. This causes the rein to be above the mouthpiece when engaged, which provides the poll relief. Unlike a baucher, a kimberwick has a mouthpiece that’s fixed bucker higher on the cheekpiece. This causes the rein to be slightly below the mouthpiece when engaged, with room to increase the leverage by lowering your hand.

Uxeter/Kimblehook

Uxeters and kimblehooks are two different types of kimberwicks with rein slots for the rider to pre-determine the amount of leverage applied before mounting.

Liverpool

Liverpool cheekpieces are a type of cheekpiece used for driving. They have a straight shank with multiple rein slots to pre-determine the amount of leverage applied. Liverpool cheekpieces also have a ring where the rein can be clipped to work as a baucher, however regardless of rein placement, this ring aids in steering by pushing on a larger area of the muzzle.

I am unable to obtain a photo of a liverpool cheekpiece at this time. If you have a bit with a liverpool cheekpiece and would be open to having it shared on this article, please contact me with some photos

Stockman / Argentine

Stockman cheekpieces are nearly identical to pelhams, except they have swept-back shanks instead of straight ones. This gives more time for the horse to respond to the leverage before it reaches its full potential of pressure. The Western version of a stockman is called an Argentine shank. With stockman/Argentine bits, riders typically use either the baucher or leverage rein instead of two sets of reins like on a pelham.

I am unable to obtain a photo of an English Stockman / Western Argentine cheekpiece at this time. If you have a bit with a either cheekpiece and would be open to having it shared on this article, please contact me with some photos

What is gag / pseudo-gag action?

Gag action is the result of a mouthpiece that is unfixed on a cheekpiece with leverage and is therefore free-moving. Like any other leverage bit, these bits engage on the poll, signaling the horse to lower its head, however, simultaneously the mouthpiece moves upward to lift the corners of the lips when engaged, signaling the horse to lift its head. Bits with pseudo-gag action don’t have unfixed mouthpieces on a leverage cheek, but they still send the same conflicting signals of “lower your head, but lift it too”. This causes horses to hollow out over time due to them being unable to find a clear release of pressure. A common example is any leverage bit with a 50:50 purchase-to-shank ratio or any leverage bit with a purchase longer than the shank. If a mechanically sound leverage bit has an improperly fitted curb strap or no curb strap, it will over-rotate, creating what can be described as pseudo-gag action. There are dozens of types of bits with gag or pseudo-gag action built into them. Below is a demonstration of a cheekpiece with gag action and the conflicting cues that arise when this bit is engaged, followed by examples of common gags, draw gags (which may appear to be snaffles but feature hooks for a rope to be threaded through them to create gag-action. These are also called ‘true/draw gags’ by some) and a combination bit—a bit with gag-action combined with a hackamore to further attempt to control a horse.

Video Credit: Emaleigh Merideth

Additional Considerations for Leverage

The main rules with leverage bits are:

The longer the shank, the more leverage you have
The shorter the shank, the more abrupt the leverage will be
The straighter the shank, the faster the full potential of leverage is used
The more curved the shank is, the more time the horse has to respond before the full potential of leverage is used

Single-jointed mouthpieces should never be paired with leverage cheekpieces. This results in a bit that when engaged, can only collapse around the jaw. If the cannons are curved, they will dig into the tongue, and if the cannons are straight, they will dig into the roof of the mouth. There is no difference in pressure regardless of if you use direct pressure or indirect pressure, and if you’re neck reining they’re still at least slightly engaged at all times.

All leverage bits should be used with a smooth curb strap, not a chain, bead, or other abrasive material. The purpose of curb straps is to prevent the bit from overrotating, and can also be an additional light signal for the horse. All signals should work off of clear cues, not discomfort or pain. Chain curb straps will pinch, beads will have a ‘bite’ to them, and rope is abrasive, making all of these and any other non-smooth option a way of controlling the horse instead of communicating with the horse.

You may have heard the phrase ‘Tom Thumb Bit,’ but what exactly is a Tom Thumb? There are three versions of Tom Thumb bits:

American Tom Thumb: Refers to a bit with a single-jointed mouthpiece with straight cannons and short, straight shanks.
European Tom Thumb: Refers to a short, swept-back shanked bit with gag action (essentially an American Junior Cowhorse). Can have any mouthpiece.
Australian/New Zealand Tom Thumb: Refers to a loose ring snaffle with prongs for steering (essentially a fulmer).

BITLESS

Sidepull

A sidepull is the snaffle of the bitless world. It has a 1:1 ratio of how much pressure the horse feels to how much you put in your rein.

Cross-Under

A cross-under has a nice idea behind it, however, the design is flawed. The intention behind them is to nudge the jaw toward the direction you’re turning as it's a common pressure point horses use with each other when one wants another to move. While they do nudge the jaw, they are incapable of fully releasing the pressure once you’ve engaged the rein unless you hop off to loosen the bridle every time. They also can’t be used for anything other than turning, which is far from the only thing our rein and bit/bitless cues should be.

Scawbrig

A scawbrig presses on the nose while tightening around the jaw area, distributing the pressure in a full circle around the horse's muzzle.

Starwheel Mechanical Hackamore

A starwheel hackamore has a mild amount of leverage, increasing or decreasing depending on where you have the reins fixed into place.

Shanked Mechanical Hackamore

A shanked hackamore has a more severe amount of leverage, with the amount depending on the type of cheekpiece.

Serreta

A serreta is a metal hackamore with ridges on the inside, originating from Spain. These ridges can range from bumps to spikes, causing pain when engaged. Traditionally these are ridden with two sets of reins, one directly connected to the serreta and another connected to a pair of shanks that are attached to the serreta to further amplify the pain. Occasionally, you may come across a serreta with no bumps or one that is covered with leather. While these are much better than the commonly spiked serreta, they don’t conform to the shape of the horses muzzle and are the only bitless option designed to sit far too low on the face (lowest point or below the nasal bone entirely), meaning they will always be ill-fitting.

I am unable to ethically obtain a photo of a serreta at this time. If you have a serreta and would be open to having it shared on this article, please contact me with some photos

Additional Considerations for Bitless

Bitless setups should have the nosepiece fitted approximately in the middle of the eye and the top of the nostril, resting on the upper base of the nasal bone.

Non-conforming or abrasive materials like rope, chains, and bike chains, will cause your bitless setup to work off of discomfort, not communication. While metal nosepieces cannot be fixed, wrapping rope in leather is a great temporary fix.

Bitless options with any form of leverage can confuse horses who haven’t been patiently taught how to respond to them. While leverage bits are easy for a horse to graduate into, bitless leverage options are tricky. This is because when engaged, the nosepiece and crownpiece press downward while the chin strap engages upward. This can confuse horses who haven’t been taught how to respond to it or horses with riders who use these for the wrong reasons. This pressure can also feel too snug on a horse's face, leading to head shyness with some horses.

Double Bridles

Two bits can seem quite medieval. However, having a snaffle and leverage bit allows you to execute more precise cues which benefits the horse and rider in disciplines requiring more finesse, such as dressage. A double bridle is made up of a bridoon/bradoon which is a snaffle with much smaller rings, and a leverage bit called a weymouth. Classically, the bridoon will have loose or fixed rings, either a single or double jointed mouthpiece, and the weymouth will have a mullen mouthpiece with straight shanks. The proper use of a double bridle allows the rider to give lateral cues with the bridoon, and cue the poll with the weymouth.

BUCKAROO HORSEMANSHIP

Buckaroo horsemanship refers to how the vaqueros of California trained their horses with the utmost precision to excel in their daily work. The majority of the time their horses work off of seat cues alone. They use ‘bridle bits’ that can appear quite scary to the uneducated eye, but let's talk about how all this works and how these cowboys get their horses ready for their bits!

Stage One - The Hackamore

A traditional hackamore comprises a bosal, a bosal hanger, and a mecate. A classic mecate is ~24ft and made of horsehair, which provides a more prominent pre-signal when the rider picks up the slack in the mecate. If the bosal is smaller than ½”, it’s called a bosalita. Typically, horses are started in a ¾” bosal and the rider gradually switches to thinner bosals/bosalitas as the horse ‘graduates’ into more precise work. The bosal appears to work like a lever; however, a hackamore is a signal tool and not meant for leverage. When engaged, the heel knot and cheeks of the bosal lift off the chin groove and the nose button shifts forward the tiniest bit. This allows the horse to respond to the position of the bosal shifting instead of having its head pulled. Only rarely does the rider need to engage the hackamore so much that the heel knot and cheeks of the bosal lift to the point that you feel a ‘tightness’ in your hand; this is when the signal turns to pressure. A hackamore is designed to ‘get in and out’ when in use, meaning you bump with your rein instead of consistently pulling. At the end of this stage, the horse should be able to neck-rein and know most of what it needs to be taught for its career as a stock horse.

*Sara Jean Wedel and her mare ‘Reba’ demonstrating the hackamore*

Stage Two - The Two Rein

The two rein is exactly as it sounds—two sets of reins. This is the stage where we introduce a bridle bit while continuing to use a hackamore. Initially, the reins aren’t connected to the bit to give the horse ample time to figure out where in their mouth they want to hold their bit and how to balance it perfectly. Once the horse has figured it out, a pair of romel reins are attached to the bit and to prevent rubbing, bosalitas are used at this stage as they fit better under the headstall. For a long time, the rider only uses the mecate, and very, very slowly, uses more of the romel over time. The ‘sub-stages’ that many horsemen and women will use to explain this are as follows:

Sub-stage 1: 75% hackamore 25% bridle
Sub-stage 2: 50% hackamore 50% bridle
Sub-stage 3: 25% hackamore 75% bridle
Sub-stage 4: 0% hackamore (still there just in case the horse gets confused) 100% bridle

*Sara Jean Wedel and her mare ‘Reba’ demonstrating the two-rein*

Stage 3 - Fully Bridled

A horse who has completed all of its training and has graduated to a bridle bit is a horse who has earned the privilege of being called a bridle horse. This entire process takes approximately 5-8 years, and often when a horse has ‘graduated’ into their bridle bit, the mecate on their final bosalita gets replaced with a get-down rope (a ~16ft rope made from horsehair), which is what bridle-horsemen and bridle-horsewomen lead their bridle horses with.

*Jeff Wedel demonstrating the bridle and get-down*

What exactly is a bridle bit?

A bridle bit (also called a signal bit) cues through the weight of the bit rather than through direct or indirect pressure. They are designed to be noticeably heavier, so first, the weight of the cheek pieces shift, followed by the weight of the mouthpiece, shifts, and these are the bit cues a bridle horse is trained to respond to. With a bridle bit, you never pick up the slack in your rein enough to engage the bit the way you would with a leverage bit. Below is an example of the most well-known bridle bit, made with a Spade mouthpiece and a Santa Barbara cheekpiece.

Regardless of your discipline, your methods, etc., the best way to make sure you are using a humane and mechanically sound bit is the visually and physically evaluate it. Ask yourself “Is this going to help me communicate with my horse, or is it going to help me control it?” Always make sure you’re aiming to communicate with your horse, instead of attempting to control it.

This just about concludes my first passion project and my first article. If you have any questions or general feedback, please contact me! Always happy to have a conversation.

*As of October 8th, 2024, I am working on demonstration videos to further explain the mechanics of all these bits. Please continue reaching out with any specific questions for me to answer in the video :)

Thank you to Agador’s Bits and Sweet Billy’s Bits for allowing me to use photos of the bits they sell. Thank you to Emaleigh Merideth, Izzy Morgan, Justin Ogden, and Seraya Sigsworth for letting me use photos of items in their personal collection! A major thank you to Sara Jean Wedel for allowing me to use her photos for the entirety of the ‘Buckaroo Horsemanship’ section, and Dover Saddlery at Moraga, California, for allowing me to stop by to take photos of their bits!

A beginner’s guide to bit mechanics