How to Correctly Fit a Bit for Any Horse, in Any Sport

You enlist the services of a saddle fitter to ensure maximum comfort for your horse … so why not a bit fitter as well?

If there’s one thing equestrians have in common, regardless of discipline, it’s the desire to do what’s best for our horses. From coaches and trainers, vets and nutritionists to dentists, chiropractors, saddle fitters and more, we employ an army of experts to help ensure our equine partners are feeling and performing their best. Where once we relied on tradition, now we increasingly turn to technology to inform our decisions, particularly when it comes to selecting equipment and tack.

Just a few decades ago, the process of buying a saddle was as simple as flipping through the pages of the tack store catalogue, choosing a model you liked the look of, and ordering it. Today we understand just how much damage an ill-fitting saddle can do, and enlisting the help of certified saddle fitters has become the norm. Increasingly, these experts are also advising on girth selection to maximize comfort and performance. But what about bits?

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As a life-long equestrian, Tammy Levasseur had never really given bits much thought. However, when she opened On The Bit Tack and Apparel near North Bay, Ontario, and buyers started turning to her for guidance about choosing a bit, she realized just how big the knowledge gap in the industry is.

“The bit is a direct link between the rider’s hands and the horse’s sensitive mouth, yet we often rely on little more than tradition or fashion when buying one,” Levasseur says. “For most of us, it’s just good old-fashioned trial-and-error until we find the magical combination of mouth style, cheek piece and materials that seems to work best for our horse.”

Her quest for knowledge – both for herself and to benefit her customers – led Levasseur to pursue a certificate in Lorinery Science, the science of bitting and bit and bridle fitting. We asked her to break down the bitting fundamentals that all riders need to know.

Equine Bit Basics

Levasseur says there are a number of areas to consider, including the class of bit (cheek piece type), mouthpiece type, and material. The action of the bit in the horse’s mouth and the feature angles within the bit and how they act on the horse lips, tongue, bars and poll play a key role as well.

Classification: Bits are divided into two different classes, depending on the type of cheek piece used.

Class I bits have an initial angle of 90 degrees when no contact has been applied. The rein and cheekpiece of the bridle are attached to the same ring and the bit mouthpiece rotates backward (caudally) in the oral cavity of the horse with rein contact. Class I bits include those with fixed cheeks such as eggbutt, D-ring and full cheek snaffles, which keep the bit stable in the horse’s mouth and assist with the turning or directional aids. Also in this class are loose ring bits, which offer more mobility in the mouth and allow the bit to re-align during riding.

Class II bits have an initial angle of approximately 0 degrees. The cheek piece of the bridle attaches to a separate ring above the ring to which the rein is attached. This produces a lever action and causes the bit to rotate forwards (rostrally) in the oral cavity with rein pressure. This class includes leverage bits such as a curb, Pelham or Baucher bits.

Mouthpiece: Most bits fall into one of three categories: single-jointed, double-jointed, and unjointed.

The mouthpiece of a single-jointed bit consists of two levers, with the joint acting as the fulcrum. This creates a “nutcracker” action with an inward force applied to the corners of the lips and pressure on the tongue.

A double-jointed bit features two fulcrum points, one on each side of the tongue, reducing the inward forces applied to the lips. The middle piece can be a variety of shapes, including a “bean” or a “plate,” and is often rotated to spread the pressure on the tongue more evenly.

An unjointed or Mullen bit has no lever action and places no pressure on the commissure of the lips. Force is applied to the tongue and bars only. Some bits have an inverted U shape or “port” in the middle, which puts pressure on the palatine arch (roof of the mouth).

Equine Bit Material

Although rubber and plastic models are available, metal bits are most common. Each metal has specific properties which should be considered when selecting a bit. For example, stainless steel is not bio-available, meaning no metal is released in the horse’s mouth. With low thermal conductivity, it takes longer for a stainless steel bit to reach the internal temperature of the horse’s mouth so it remains cold longer. So-called “sweet iron” has a bio-available oxide which gives it a taste that may encourage acceptance in some horses.

Correctly Fitting a Horse’s Bit

Correctly fitting a bit is at least as important as choosing the right type of bit. Most of us were taught to assess the height of the bit in the horse’s mouth by the number of lip wrinkles: one wrinkle or less, the bit is too low; more than two wrinkles, the bit is likely too high. With many other factors to consider, however, seeking expert advice can save you time, money and frustration in the long run.

“My recommendation to anyone would be to invest in a consultation with a certified bit fitter who can come to your barn and evaluate your horse in person,” Levasseur says. “They’ll ask questions about your current training regime, goals, and any issues you are having, and will observe your horse being ridden in your current bit. They’ll examine your horse’s mouth for any structural anomalies or physical problems, and will measure the mouth width and the height of the interdental space (the “bars” of the mouth). They’ll also check the height and shape of your horse’s palatine arch, as that plays a big role in determining the optimal bit thickness and shape.”

Horses are nose breathers and cannot breathe and swallow at the same time. The horse’s tongue fills the entire oral cavity; no magical space exists within the mouth for the bit. Room is created only by compression of the tongue, so it’s extremely important to be aware of any structural anomalies such as a low palate or small interdental space. The tongue cushions the bars when the horse is bitted and the bit does not rest directly on the bars except when the tongue is pulled back in the horse’s mouth. This is one of the reasons correct bit fitting is so important – to allow space for the tongue to comfortably sit on the floor of the oral cavity. “There are a lot of bit-fitting myths out there, like the belief that a thicker bit is more gentle and comfortable for the horse. However, if your horse has a low palate or small interdental space, a thinner bit may actually be more comfortable.”

When conducting a bit-fitting evaluation, Levasseur first measures the width of the horse’s mouth to determine the optimal bit size. In general, the bit should be .25 inches wider than the mouth, so a horse with a 5.25-inch mouth requires a 5.5-inch bit. She manually assesses the anatomy of the tongue and mouth, including height and shape of the palatine arch, and uses her fingers to determine the height of the interdental space. She then measures her fingers to record an exact figure.

“Unfortunately, there aren’t many bit fitters in Canada yet, so many people don’t have access to this type of service,” she says. “That’s why it’s so important for riders to educate ourselves as much as possible about bitting options, or to use online consultation services such as the one offered by Neue Schule [nsbits.com/bitting-consultation/]. Knowledge is power.”