How a Horse Bit Works

“There are many types of bits for many different disciplines, but the severity of ALL bits lies in the hands holding them.”

— Monty Roberts

A tack wall gives you a hundred bits and almost no information. Cheek pieces, mouthpieces, attachments, materials. It is easy to stand there and have no idea which one belongs in your horse’s mouth.

Before the bit, the skull.

The equine skull

Whatever we put on a horse interacts with it physically, so the anatomy comes first.

The equine skull is the mandible — the lower jaw; the maxilla — the upper jaw and the smaller bones associated with it, including the eye sockets and the nasal bone; and the teeth.

Two more things matter when you are choosing a bit. The atlas, which is the first cervical vertebra, the poll, between the ears. And the tongue.

Several pressure points sit inside that area, and a bit acts on them in one way or another. Which ones, and how hard, is the whole question.

Horses have preferences

Each horse reacts differently to each pressure point, and most have a clear preference for one pressure over another. The bit that works is the one that leaves a relaxed, responsive horse — not a horse enduring the equipment.

Reading that takes knowing your horse: the signs of pain, of discomfort, of relaxation, and what its behavior normally looks like.

Preferences move. Age, fitness, discipline and training all change them. A bit that suited a horse at five may not suit the same horse at twelve.

And the hands are part of it. That is what Roberts is saying above, and it is the part of the equation no bit can fix.

What’s in a bit

A bit has two parts.

The cheek piece is what you see on the outside of the mouth. The mouthpiece sits inside, in the interdental space — the gap where there are no teeth.

The exception is a hackamore, which does not interact with the mouth at all. Depending on the type, it works on the nasal bone and the poll instead.

Bits come as combinations of the two, and they function both individually and together. Mouthpieces are the part to understand first: used in a way they were not intended for, they cause pain, damage and stress. Once you know the pressure points of the skull and what a mouthpiece does, you can pick up any bit and work out how it will act on your horse.

Every common mouthpiece and cheek piece, and what each one does →