Finding the Right Sized Bit


The bit operates like a communication channel between rider and horse. As the mouth is one of the most sensitive parts of the horse's body it is important to treat it very carefully. A bit should be sized and fitted to the individual anatomic shape of the mouth as well as to its characteristic needs. The basic requirement for the correct bit choice is a healthy and properly trained horse.

When choosing a bit, think about the horse who you will be using it with. The size of their mouth, the thickness of their tongue, high versus a low palate, the width and depth of the bars, their training level, personality and what type of metal they prefer are all factors to consider when searching for the right bit for your horse.

If the horse can not close his mouth around the bit, it is a sign the bit is too wide for his mouth. A bit too long with have too much movement and misplace the pressure on to the narrow bony bars of the horse’s mouth. A bit too short will pinch the lips.

Most horses will take a bit between 4-3/4” to 5-1/2”. When fitting a bit, there should be roughly one index finger of width between the lips and the edge of the bit, roughly ½”, for loose rings. Fixed ring bit can have less room.


There are two things to consider for choosing the correct bit size:

  • Thickness

  • Size


The thickness of a bit should be adapted to the anatomic needs of your horse. Research by SPRENGER and the Veterinary University of Hanover found that the oral cavity of horses is fairly small and the available space for a bit can be very limited.

Find the right thickness for your horse’s bit by asking your horse's vet for advice and/or try the “2-finger-test”.

Carefully put your index and middle finger together and insert them in the horse’s mouth at the point where the bit usually lies. Pressure on both fingers (the small gap between the upper and lower jawbone) requires a thinner mouthpiece (14 – 16 mm).

Little or no pressure on fingers (larger gap) allows a thicker mouthpiece (16 - 18 mm). Using a too thick bit can exert pressure on the sensitive palate and can also cause bruises and injuries. The horse might react with head tossing, gaping its mouth or jerking on the reins.


Fitting Different Bits

Loose Ring Snaffles

Loose ring snaffles should not leave more than 5 mm space between the corners of the mouth and the bit ring on each side. Roughly the size of a pinky finger. It should not be too tight, since it must not pinch the corners of the mouth. The ring should always be able to move freely.

Bits with Fixed Cheeks

Bits with fixed cheeks such as Eggbutt, D-Ring, Full Cheek, Pelham or Weymouth bits should fit closely to both mouth corners and must, therefore, be chosen smaller than loose ring snaffles. Due to the contact of the side part to the corner of the mouth, the rider achieves additional support from rein aids.

Double Bridles

The double bridle consists of a Weymouth and a bradoon. The bradoon should equal the standard snaffle in size and shape because it lies at the same position in the horse’s mouth. The Weymouth is positioned a little bit lower where the horse’s head gets thinner. We recommend choosing the Weymouth 0.5 to 1 cm smaller than the bradoon in order to achieve the best possible effect and to make the horse feel comfortable.