Find the Bit That Fits

Bits are a critical piece of equipment for your dressage horse, but finding and fitting the right one can be a daunting task.

Since bits provide an important means of communication, it’s critical that they fit the horse correctly and are comfortable.

Bits have been a cornerstone of riding equipment for thousands of years, and remarkably little has changed over the centuries as ancient horsemen to modern dressage enthusiasts have all used variations of the same theme: a metal mouthpiece with reins attached to often elaborate cheekpieces. In today’s dressage arena, bridles are depended on as a primary means of communication between rider and horse, making it critical for a bit to fit well and be comfortable for each individual mount. Choose wisely and a rider has a good chance of having a happy athlete as a partner. Choose poorly and one may be left with a miserable mount who acts out or simply doesn’t perform up to expectations in an effort to avoid discomfort (or even pain) from a badly fitting bit. But with so much on the line and so many options available, how does anyone find the perfect match?

“Open any catalog and you’ll see page after page with hundreds of bits to possibly choose from, with new concepts and styles coming out all the time,” said Hilary Clayton, BVMS, PhD, Diplomate ACVSMR, MRCVS, who served as the Mary Anne McPhail Dressage Chair in Equine Sports Medicine at Michigan State University’s College of Veterinary Medicine from 1997 until she retired in 2014. “So understandably it can be a daunting and expensive task for anyone to try to figure out what bits may or may not work for your horse.”

First Things First

Clayton is not only a renowned researcher who has extensively studied the anatomy of horses’ mouths and the mechanical action of bits, but she’s also put the knowledge she gained into practice in the saddle as an accomplished USDF bronze, silver and gold medalist. She recommends that riders try to eliminate guesswork by doing as much homework as possible to determine what may work best for their own horses. It’s much more complicated than simply choosing a shiny new bit off a store rack, using the same bit on every horse or succumbing to a fad just because another rider claimed to have success with it. “First, riders should understand how form equals function,” she said. “In the most general sense, snaffle bits act with direct pressure on the mouth, whereby curb bits employ an element of leverage. Mouthpieces can be jointed [single or double] or unjointed [mullen mouth] and made of a wide variety of metals or feature other materials, such as plastic, rubber and leather. Cheekpieces can also vary just as much as mouthpieces, affecting the amount of leverage placed on the top of the head, with bits that have a shank exerting the most pressure.

“It’s important to remember that the basic shape of the mouthpiece, whether it has a single joint, double joint or no joint, isn’t so much a matter of different severity but instead reflects how the bit will lie in the horse’s mouth and across his tongue,” Clayton continued. “For instance, one of the most common mouthpieces has a single joint, which actually forms a V shape when pressure is applied through the reins. In contrast, a double-jointed mouthpiece forms more of a U shape over the tongue. Our research indicates that the single-jointed shape does not conform well to the horse’s tongue and the apex of the joint can even poke upward uncomfortably with a nutcracker action into the horse’s palate. So, right off the bat, a single-jointed snaffle, which so many of us were taught to believe should be a tack-box staple and a very kind bit to use, in reality may not be a good choice for some horses.”

Deike Bräutigam is a licensed trainer and Prix St. Georges dressage rider who has served as a bit expert and advisor for Herm. Sprenger, one of the world’s leading bit manufacturers. “When choosing a bit, additional things to consider include the stage of training of horse and rider, the character and temperament of the horse and any existing problems with contact and acceptance of the bit. Identifying and setting some parameters is a great way to start to narrow down the many choices out there,” said Bräutigam. “Remember that finding the ‘perfect bit’ can never compensate for a lack of riding skills. A bit is only as strong as the rider’s hands that are using it. One of the biggest mistakes we see people make is thinking that rideability problems can be solved with a new or ‘special’ bit.”

Trusted by many high-performance riders up and down the East Coast to help fit their horses with the right equipment, Beth Haist, founder of The Horse of Course Inc., agreed that bits can never be an excuse or substitute for basic training challenges. “For instance, one of the common complaints I hear relates to the horse’s tongue, and I believe that all tongue issues are a straightness and tension concern, not a bit issue. A bit can never cure training problems, so my philosophy is always to try to use the mildest bit possible, not just try something new and harsher.”

When evaluating a possible bit for a mount, Haist encourages her clients to understand the five points of control on the horse’s head, which include the curb groove, the corners of the mouth, the bars, the palate and the poll, and how a particular bit will affect each of those points. “Of these five points, the palate is the most sensitive,” she explained. “Take a look at the bit and endeavor to understand how the bit will activate in the horse’s mouth. How is it designed to work? Does it go strongly up into the palate? Does it put pinpoint pressure on the tongue?”

Take a Closer Look 

Walk into any tack store, like The Tack Shack of Ocala (pictured), and you’ll see an overwhelming number of bit options. (Credit: Jennifer M. Keeler)

Clayton explained a few factors for riders to consider before heading to the tack store. “First take a look at your horse’s mouth. Carefully lift his lips on either side of the mouth and look at the space between the upper and lower jaws—any bit has to be able to easily and comfortably fit within that space. It can be difficult to determine exactly how much room there is and there may very well be less than you think,” she said. “Interestingly, I did some research with X-rays and measurements of the oral cavity on a variety of horses and found that you can’t make assumptions about the shape and size of a horse’s mouth just by looking at his overall body size. We found small ponies with big mouths, huge warmbloods with very small oral cavities and everything in between. Also, some horses have a very arched palate on the roof of their mouth, while others are quite flat. These horses are the ones who will have a problem with single-jointed bits because there isn’t as much room to accommodate the motion of the joint’s nutcracker action.” 

Bräutigam noted that a similar study done by Herm. Sprenger with the Veterinary University of Hannover, in Germany, measured more than 70 horses’ heads and found comparable results. “In reality, the oral cavity is small, the tongue nearly fills the mouth and the available space for a bit is actually quite limited. Therefore, it is important to adjust the thickness and size of the bit to fit the actual conditions of your horse’s mouth.” Herm. Sprenger recommends that riders try the “two-finger test”: carefully insert two fingers in the horse’s mouth at the point where the bit usually lies. Mouths with a small gap between the upper and lower jawbone will exert strong pressure on the fingers, and will require a bit with a narrower mouthpiece in order to fit comfortably.

In these cases, what is often believed to be the mildest bit available—a big, fat snaffle—is actually much too wide for the available space, making it uncomfortable for the horse. “For many of us growing up, we were indoctrinated that a fatter bit is milder because it spreads the pressure over a wider area, but it turns out that’s only true up to a point,” Clayton explained. “A very fat bit can simply be too big for the mouth and too-narrow a mouthpiece can be too harsh, so what we really want is something in the middle. Now that we know more about the mechanics, I believe that most bits today on the market are more correctly sized in this range.”

If peering inside and poking around in your horse’s mouth sound daunting, Clayton encouraged riders to seek help from their equine dentist or veterinarian. “Ask him to take a look at your horse’s mouth, as he will be familiar with the anatomy and most likely will have a general idea of the mechanics of bits and how they are affecting your horse. An exam can certainly help spot any sores or bruising from a bit that’s not working well for your horse, but a note of caution: Just because a horse has an ulcer on his tongue doesn’t mean you can assume it’s a bit problem. Usually it’s a tooth issue, but when you add a bit into the mix it can exacerbate an existing situation,” she noted. “So regular dental maintenance, such as floating teeth, is important. Sharp edges on the molars can become especially painful when a bit applies extra pressure on the cheeks and can even increase the chances of a horse accidentally biting himself and bleeding.” 

Getting the Right Fit

The next step in the journey to finding the right bit is figuring out the right size. Bit size is determined by measuring the distance across the mouthpiece between the inside of each cheekpiece. Several manufacturers offer a special tool (available through retailers) to measure the width of a horse’s mouth and help to accurately determine proper bit size, but a piece of string or wooden dowel can also be used. Measure the distance through the mouth between the corners of the lips and then choose a bit size that’s slightly larger than the actual measurement of the mouth, up to about 1 centimeter, or a half-inch, wider. Clayton reminds riders that any kind of jointed mouthpiece will hang slightly down on the tongue when in the mouth, so a bit of extra width may be needed to allow for this. “And you never want it to be too narrow, which will cause it to press against the sides of the horse’s face and push the inside of the cheeks between the teeth. This can be very painful,” she explained. “Also, with a curb, I particularly like a bit with the upper branches that curve away from the cheeks to allow for even more room.”

But just as important as choosing a bit that’s not too small is avoiding one that is too big, as it can then hang down too far in the mouth or slide too far sideways when pressure is exerted on a single rein. “We recommend 5 millimeters of space between the corner of the horse’s mouth and the bit ring on each side,” added Bräutigam. “But bits with fixed cheekpieces, such as eggbutts and D-rings, can be chosen a size smaller than a loose-ring snaffle for better fit and to achieve additional support from the rider’s rein aids. We see this mistake made quite often: where riders choose too large of a bit width-wise.” Haist agreed. “I see a lot of people putting curbs in their horses’ mouths that are just too wide. Take a look under your horse’s jaw and see how surprisingly narrow the bars are. If a bit is designed to work with the outer sides of the mouthpiece directly on the bars, but the bit is way too big, what ends up actually sitting on the bars is the completely wrong area of the mouthpiece from how it was designed to optimally function.

“Also remember that there are two positions in the horse’s mouth: the ‘on’ position and the ‘off’ position,” Haist continued. “The off position is when the bit is just hanging on the bridle in the horse’s mouth, whereas the on position is when you gather up the reins and the bit lifts and moves up in the horse’s mouth. The way a bit fits and lays in the horse’s mouth will change, sometimes dramatically, between these two positions, so this all needs to be taken into account when making an evaluation.”

Next is to make sure the bit is adjusted to the proper height in the horse’s mouth. “For snaffles, adjust the bridle cheekpieces so that the bit sits right up into the corners of the lips. You don’t want to see a big ‘smile,’ but only that the bit very slightly raises the corner with perhaps one wrinkle,” said Clayton. “What horses especially don’t like is to have the bit down low on their tongues, because then they are forever fiddling with it and can even easily put their tongues over it.”

Clayton also outlined some special fitting considerations for bits in a double bridle. “I like to see a slightly wider-size mouthpiece for the curb than the bridoon, then adjust the two bits with the bridoon a little higher than the curb. Even though it’s higher, if the bridoon is jointed it’s going to hang down on top of or slightly over the mouthpiece of the curb,” she explained. “This means that everything takes up more space in the mouth, and there are some horses with small mouths who simply can’t tolerate all the metal. It’s the biggest fitting problem I see with the double bridle, and you can try different styles and adjustments, but some horses just can’t wear it. That’s one reason why I think it’s so great that the USEF allows snaffle bridles to be used all the way through Grand Prix, because it’s just not a training situation—for some horses it’s an issue of physical comfort. It’s unfortunate for any horse to be excluded from competition simply because he has a small oral cavity, not because he’s not well trained.” 

Taking a Test Drive

A key to finding the right bit is identifying the correct size, which is determined by measuring the distance across the mouthpiece between the inside of each cheekpiece. In this case, the size of this bit pictured is 5 ½ inches. (Credit: Jennifer M. Keeler)

Once you have an idea of the basic conformation of your horse’s mouth as well as the proper bit size needed, the next decision will be to choose from the dizzying array of styles. To help navigate the seemingly endless choices of curvatures and ports, joints and rollers and loose-rings to Weymouths, bit manufacturers offer detailed handbooks and pamphlets to give riders guidance in choosing the right product. But for many horses, finding the right bit will still come down to good old-fashioned trial and error. 

This can be an expensive process: Most retailers don’t allow the return of a used bit (even if only tried for one brief trial ride), and with the cost of new bits ranging from about $30 to several hundred dollars each, many riders can’t afford to purchase a new bit each week in an ongoing effort to find what makes their horses happy. “I think the best advice I can give is for people to have a few basic styles in their bit box that they have used successfully in the past and then take those to try to use as a starting point,” said Clayton. “From there, change just one element at a time to try to hopefully find the right combination of features. Also, be creative. Network with friends or borrow from your trainer to try a particular style before committing to the purchase of a brand-new one, or even try to find used bits for a reduced price.” (See sidebar p. 44)

To further assist their customers, some retailers, including Herm. Sprenger, have developed a method to “test-drive” various bits. Select Herm. Sprenger retailers feature test centers that offer a selection of different bit variations that, for a small fee, a rider can borrow to try out on his or her own horse. This rental program provides an opportunity to test a bit over several days without a commitment to purchase if it ends up not being the right match. “When a bit is purchased without an opportunity to actually try it first and it doesn’t end up working for that horse, the bit is never used again and the money was wasted,“ said Bräutigam. “Our test-center program gives our customers the chance to try new styles for a fraction of the cost of purchasing a single bit, which we believe helps riders make the best possible choice for their horse in the long run.”

There’s no doubt that with a dressage horse’s training, performance and even happiness on the line, finding the right bit can be an intimidating and frustrating decision for riders. 

“Everyone’s trying to get an edge, and it’s easy to get sucked into fancy new styles for a quick fix, but it’s very hard to actually prove that one design is better than another,” said Clayton. “Don’t assume that just because something works for someone’s horse that it will work for yours. Yes, this process can take some time and patience, but we owe it to our horses to educate ourselves and try to choose wisely, as this can be one of the most important training decisions we make.” 

Metal Matters

Bit mouthpieces range from very thin to very thick, but in some cases what is often believed to be the least severe—a big, fat snaffle—may actually be too wide for the available space in the horse’s mouth, causing discomfort. (Credit: Jennifer M. Keeler)

The metal composition of bits has come a long way from the days of traditional stainless steel with the occasional option for copper. Even with a multitude of modern materials now available, the primary purposes for the material used for a bit is to have a smooth surface, encourage the chewing activity (e.g., by oxidation)and, of course, be harmless for use in the horse’s mouth, said Bräutigam. Here are some of the common metals seen in the manufacture of bits:

Stainless steel and titanium have good strength and are neutral in taste, but provide no oxidation to promote salivation. “It’s a cold bit in the horse’s mouth,” said Haist. 

German silver (which is a copper, zinc and nickel alloy) has good strength with better oxidation.

Aluminum bronze includes all golden-colored copper alloys except German silver and Aurigan. Traditionally believed to enhance salivation, copper is a relatively soft material that is often hardened with aluminum, which actually inhibits the oxidation properties of the copper. Haist pointed out that copper bits must actually be composed of a majority of copper (as opposed to a mixture of other metals) in order to warm to the temperature of the horse’s mouth.

Sensogan and Aurigan (which are composed of around 75 percent and 85 percent copper, respectively) were specifically developed by Herm. Sprenger for use in a horse’s mouth, and have been proven and tested by the Veterinary University of Hannover and the German Riding School in Warendorf. According to Bräutigam, these patented materials employ many ideal features for a bit, including high strength for a long life span. They are also nickel and aluminium free, nontoxic and have excellent oxidation properties to encourage the production of saliva and chewing activity of the horse. 

Don’t Wear It Out

With the considerable cost of new bits, trying to find used bits may be a money-saving option for riders as long as some precautions are taken. “Buying a second-hand bit is OK as long as you inspect it to make sure there aren’t any sharp edges or wear marks that may cause injuries in the horse’s mouth,” said Bräutigam. “It’s recommended to clean it thoroughly either with disinfectant or by using a nontoxic polishing paste for metals.”

Bräutigam noted that the same principles apply when inspecting a bit to determine if it needs to be replaced. “You should replace a bit when it shows sharp edges on the mouthpiece, in the ring holes or in the eyes of the link/joint, or if there are any cracks or deformation,” she noted. Haist explained that this can be of particular concern with copper bits. “Because copper tends to be a soft metal, when you have a copper mouthpiece with stainless-steel rings, the stronger steel will wear against the copper so you must check around the hole where the cheekpiece goes through the mouthpiece to make sure it’s not getting sharp. If that happens, it must be discarded.” Clayton agreed, adding, “Check the function of any joints, as older bits can sometimes become worn thin near the joints, where there was movement. But in general I think bits today, especially the higher-end products, are manufactured much better than they used to be and can be expected to last a very long time.”

When It All Goes Wrong

Choosing the right bit allows for effective communication through the reins between rider and horse, which is a basic requirement for correct riding and training. But poor bitting choices not only can result in a lack of effectiveness of the aids and poor scores in the show ring, but they also can lead to physical pain and mental stress on the horse as he faces the prospect of discomfort every time the bridle is put on. “To some degree, acceptance of the bit can depend upon the sensitivity of each horse—some are happy with whatever they are ridden with, some are extremely sensitive,” said Bräutigam. “Regardless, a bit should be sized and fitted to the individual shape of a horse’s mouth and should never be uncomfortable or awkward in any way, because problems with the bit can affect the entire rideability and performance of the horse.”

If a horse is uncomfortable with a bit, he can exhibit obvious symptoms: head-tossing, gaping his mouth, crossing his jaw, jerking on the reins and sticking his tongue out, just to name a few. But the signs may also be more subtle, such as a reluctance to work, hesitation to step into the bit with confidence, coming behind the bit or overreacting to certain rein aids. “The only question I ever ask when I help riders find a bit for their horse is, ‘how does your horse take the contact?’” said Haist. “For me it is the most important question and it speaks volumes about figuring out which direction to go and in trying to determine which bit to recommend.”

Clayton believes that many resistances horses display are actually a way of trying to relieve pressure caused by the bit on the palate. “I’ve seen horses lean on the bit because they’re trying to embed the bit in their tongue and get it away from the roof of their mouth,” she said. “Even though soft tissues, such as the tongue, are very sensitive, they are much better suited to absorbing the pressure of a bit than the jawbones or the roof of the mouth where there’s very little cushioning tissue. “When there’s a problem, a rider’s first assumption tends to be that it’s a behavior issue and often the first thing that is done is to tighten the noseband, which can actually make a situation even worse if it’s related to a poor-fitting bit because it just squeezes everything together even more. As a general rule, I think equestrians should always take measures to rule out a veterinary or pain-related issue before anything else.”

Is My Bit Legal?

As the national governing body for equestrian sport, the USEF is in charge of making and enforcing rules for USEF/USDF-licensed dressage competitions, including the rules determining legality of saddlery and equipment. The dressage division of the USEF Rule Book includes four full pages of bit diagrams for members to try to navigate the waters of what’s legal and what’s not. At the epicenter of the maze of rules is Hallye Griffin, USEF managing director of dressage, who has been fielding the popular question of “is my bit legal?” for years. “No doubt about it, questions about bit legality are the majority of inquiries we receive in our department,” said Griffin. “Obviously, bits are an integral piece of equipment in our sport and we try to be very specific in our discipline rules because there’s a lot on the line, including elimination if a bit used at a competition is determined to be illegal.

“The sheer number and types of bits is daunting, and that level of detail in the rules can also be intimidating for people to review and understand,” she continued. “There are always new bits and brands coming on the market, and we do our best to keep up with what’s going on and review new products, but it’s impossible to cover every possibility and specific brand out there. In addition, misconceptions tend to persist for quite some time, such as the ‘mixed metals’ rule, which was removed over a decade ago but we still get questions about it. The rules do change on a regular basis, so even though it’s a challenge, it’s important for members to make an effort to review the latest information in our Rule Book.”

If riders have questions about a bit they’re considering using or purchasing, what should they do? “Contact our customer care center at USEF, and they will put you in touch with a member of the dressage department staff,” Griffin explained. “The best thing to do is to send a picture and/or a website link to the particular bit in question with the brand name if possible. Requests need to be in writing because it can be very difficult to accurately describe a bit just over the phone. Also, when we respond, remember that you can print out the email and take it to the show with you, which can be a useful thing to have especially if it’s a new type or brand of bit that may be questioned by an official. In addition, we are in the final stages of creating an interactive FAQ document, which has been in development for two years. We hope to have it published soon on our website [usef .org], and that it will be a useful tool not only for riders but also for officials.”






Screenshot 2024-03-25 at 9.28
Infographic: What is Myofibrillar Myopathy?
horse week
The Art of Freestyle Dancing with Horses
The Many Talents of Matt McLaughlin
Unlock Your Riding Potential with Feldenkrais Awareness Through Movement®


Ashley Holzer USA Valentine
Updates to U.S. Dressage Team Short List for Paris 2024 Olympic Games
Are lumps or swellings under the jaw reason for concern?
Anna Marek and Fayvel
Anna Marek: Working Her Way to the Top
Dressage Basics: The 20-by-60-Meter Dressage Arena and 20-Meter Circles