How to Fit a Myler Bit Size

The goal of Myler Bits is to ensure the horse has maximum comfort in its mouth. The first step to achieving this goal is to make sure the horse has the correctly fitted mouthpiece size. Before purchasing a bit, always measure the size of your horse’s mouth, unless you are already using Myler Bits and have no doubts regarding their size.

Myler bits fit a bit differently than traditional bits because they have a distinct curve in the mouthpiece that leaves more room for the tongue. Additionally, a Myler bit is ⅛” larger than its stated size, as the Mylers want to ensure that the mouthpiece protrudes by at least ⅛” to ¼” on each side of the mouth. In order to take the measurement correctly, you will need a wooden dowel or the handle of a wooden spoon.

1. Insert the dowel into the horse’s mouth where the bit normally rests.
2. Wait for the horse to relax and stop chewing.
3. Mark the dowel on both sides of the mouth where the lips end.
4. Slide the dowel out and measure the distance between the marked points.

The most common size is 5”, followed by 5 ½” and 4 ¾”. Choose the size closest to the measured distance, but pick a larger size rather than a smaller one to ensure the bit will not be too tight.

In a correctly fitted bit, about ⅛” to ¼” of the mouthpiece protrudes from both sides of the horse’s mouth when the bridle is well-adjusted and the bit rests in the center of the mouth. The cheek pieces should not fit too tightly, as they can cause chafing or cuts on the horse’s cheeks or lips. There should be some clearance between the ring and the horse’s mouth. If you feel that the bit looks too small or too large, even though you have measured correctly, check the fit of the bridle. If the bridle sits too high or too low, it will affect how the bit fits in the horse’s mouth.

Every horse is built a little differently. Although 5” has long been the “average” size among mouthpieces, do not assume that 5” will fit your horse too. Prominent lips, a narrow mouth, or thick lips can affect the bit size.

If the size you need is not available in the standard cheek piece/mouthpiece combination, please contact JNBT or Myler directly, where you can order a custom-made version.