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Bit & Bridle Fit 101

When was the last time you considered the fit of the bit and bridle you use on your horse? This is one aspect of our sport equally important to saddle fit, yet is often overlooked.

What is the Goal?

There are two primary factors in considering the fit of both bits and bridles: welfare (which should always come first) and biomechanics. All of the aspects I'll cover here are rooted from one or both of these key goals.

Ultimately, we want to achieve a harmonious connection with our horses, and the bit and/or bridle is an important tool for doing so. Humans have been using bits and bitless bridles on horses since we first domesticated them in 3500 BC. We have learned a great deal since then about how the type and fit of bits and bridles affect each horse individually, and I would like to share some of the basics with you!


I will not go into details on anatomy (if you want a refresher on the basics, give it a Google search), but I will preface this section by saying this- no other part of the horse's anatomy has as many sensitive areas as the head. This in itself should draw attention to the importance of proper bridle fit as it relates to the key welfare and biomechanics goals I brought up earlier.

  1. Crown Piece This component bears the weight of the bit and bridle and applies pressure to the poll and behind the ears. Correct Fit: - "Splits" where the billets for the cheek pieces and throatlatch begin should branch off below the base of the ear. - Must sit flush with the horse. Any areas that gap or bridge (like some poll relief bridles) will create additional pressure points elsewhere. - Four fingers (flat) should fit between the crown piece and the horse's poll when the entire bridle is "done up". If you can't do so comfortably, it is likely the noseband and/or other components are too tight. General Recommendation: Don't be fooled by the marketing of the over-engineered anatomical crown pieces. They are not made to fit every horse and often do more harm than good, unfortunately. You can't go wrong with a traditional straight crown piece with supple leather.

  2. Brow Band This, along with the throatlatch, serve only as security for the bridle. This helps the bridle stay on the horse in the event of a fall or otherwise extreme circumstance. Correct Fit: - Should be able to fit a flat hand between the horse's forehead and the browband without any tension in the leather. Too snug and this will press the crown piece into the back of the ears and pull the cheek pieces towards the eyes. - Placement between the base of the ear and the TMJ. Should connect to the crown piece above the "splits". General Recommendation: When in doubt, size up. If ordering a browband separately, make sure the channel width is the right size for your crown piece so it stays in place.

  3. Cheek Piece This connects the bit to the bridle. Correct Fit: - Buckles should sit eye-level. If too high, this will put pressure on the sensitive TMJ, or worse, can push the browband into the ears. - Cheek piece and cavesson (noseband) buckles should not be stacked, as this creates an obvious pressure point. A lot of sensitive nerves run along this area. General Recommendation: If your cheek pieces are too long or short but your bridle otherwise is an appropriate size, contact your local leathercraft expert (like me!) and they can make adjustments without having to buy new.

  4. Cavesson (Noseband) Originally created for several reasons: to prevent horses breaking their jaw in the event of a fall in battle or over fences, as a combination halter/bridle for trail and military horses, and as a restricting device to induce pain (in "ancient times" a drop noseband with sharp metal inlays would be applied tightly, thought to increase sensitivity to the bit). Today, this is used for attachments (like martingales and nose nets) and is required in some competitions. Correct Fit: - Should be able to fit two fingers (stacked) between nasal bone and noseband when fastened. - Noseband should be placed more than 1 thumb's width from the facial crest and more than 4 fingers above the nostril. Any lower and pressure from the noseband will be at high risk of fracturing the nasal bone. General Recommendation: Ditch the noseband when hacking/schooling at home. Even when fit correctly this can exert a tremendous amount of pressure when the horse performs natural movements like yawning or chewing.

  5. Throatlatch This, like the browband, serves as security for the bridle. Correct Fit: - Should be able to fit a fist between the horse's jaw and the throatlatch. - Ensure the browband sits above the "splits" where the throatlatch breaks off from the crown piece else the throatlatch will push it up into the ear, which can pinch. General Recommendation: While we don't want this snug, too loose can be irritating for your horse as it "flops" around and can increase the risk of getting caught on something.


The mouth is undoubtedly a very sensitive part of the horse and what is so often left unconsidered when selecting a bit for a horse is their unique interdental conformation (that is, what the inside of their mouth is like). This is where certified bit fitters (like me!) really come in handy, as each horse can be assessed as an individual. I can share some generalized basics on fitting bits here, though, some of which may come as a surprise and I hope I can dispel some myths.

  1. Mouthpiece Size There are some gadgets on the market to help you measure your horse's bit size, but because some measure their bits differently and mouthpiece contour can affect this, it is best to have a bit fitter evaluate if you are looking to size a new bit. On your own you can check your bits to make sure they fit correctly: - For a loose ring bit, you should have approx. 1/4" between the horse's lips and the hole which the loose ring passes through, on each side. - For a fixed cheek bit, you should have roughly 1/8" between the horse's lips and the cheek of the bit. Any less, and it will press inward on the horse's face, any more and it will slide around too much in their mouth.

  2. Mouthpiece Thickness I am sure you have heard that thick bits are more kind than thin bits. While this is true for pressure distribution, you must remember that horses were not made to have bits in their mouth. In fact, some horses have no room at all for a bit. A study was conducted that showed, on average, horses can accommodate a 11mm - 17mm diameter mouthpiece (link here: - Too thin and this will be quite sharp. This can do a lot of damage - particularly with a rough mouthpiece and rough hands. - Too thick and this will put pressure on the palate, compress the tongue, and can have a numbing effect - even without pressure from the reins.

  3. Position in Mouth I am sure many of you have heard of the "two wrinkle rule". Problem is, every horse has a different length smile and degree of elasticity to their lips. So this may be too high or too low in their mouth. The correct placement can be a bit tricky so you will need to have a certified fitter evaluate. On your own, however, some tips: - If your horse has canines (geldings will but some mares do too) make sure the bit is positioned high enough so it cannot contact these teeth no matter what forces are acting on it. - The bit should not be so high that it contacts the molars. - A snaffle bit bit should not be so high that there is no slack in the cheek pieces when rein tension is applied.

  4. Leverage Cheek Pieces

Snaffles apply direct action to the mouth, where leverage bits like pelhams and weymouths work on indirect pressure - they have a purchase and shank that rotate the mouthpiece and leverage resistance from the poll and jaw to apply pressure to the mouth. The previously mentioned rules of fit apply, but the curb chain (or back strap) must be fit correctly in order for the leverage system to work as intended, with optimized pressure to poll and lower jaw.

Curb chain should lie flat and be adjusted so that when rein tension is applied, the cheek piece does not rotate more than 45 degrees.

If you are curious to learn more about different cheek pieces, mouth pieces, how a gag vs. leverage bit works, or a deep dive on another bit/bridle topic, let me know, I can do a "part two"!

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