Choosing the right bit for your horse

Why bit selection matters so much

A poorly fitting or overly severe bit causes pressure on the tongue, bars or palate. Research by the FEI shows that up to 70% of behavioural problems under saddle have a painful cause, and the bit consistently ranks high on that list. Conversely, a well-fitting bit strengthens the connection and enables a light aid. Before reaching for a new bit in response to resistance or jaw tension, it's wise to critically assess the current bit first and have an equine dentist take a look. Record your findings in the horse profile in EquiSight so you can identify patterns later on.

Determining the correct mouth size

The most common mistake is estimating the mouth size. Always measure it accurately with a ruler or a dedicated bit-sizing gauge. Place the gauge in the corners of your horse's mouth and read off the width. Most horses fall between 12 and 14.5 cm. The bit should protrude no more than 5 mm on each side — less will pinch, more will chafe and reduce control. Ponies often measure 11 to 12 cm, warmbloods 13 to 14 cm. Record this measurement in the horse profile so you can instantly select the right size with every purchase.

Bit types and how they work

There are three main categories relevant to most horse owners:

• Snaffle bit: acts on the tongue and corners of the mouth, soft and direct — the standard starting point for young horses and beginners.
• Double bridle (with pelham or full dressage bridle): combines snaffle and curb reins, offering greater refinement but requiring experience from the rider.
• Gag bit: increases the action on the corners of the mouth and the nasal bone, popular in show jumping but requiring soft hands.
• Loose ring vs. fixed D-ring: a loose ring allows more movement and encourages chewing; a D-ring keeps the bit more stable in the mouth.
• Stainless steel vs. synthetic: stainless steel is durable and taste-neutral; copper or sweet iron stimulates saliva production and acceptance.

Signs that a bit doesn't fit

Your horse usually gives clear signals when a bit is uncomfortable. Watch out for the following behaviours:

• Tongue hanging over the bit or strong pressure against the bit.
• Jaw tension, teeth grinding or constantly opening the mouth.
• Head shaking when rein contact is applied.
• Resistance when tacking up or accepting the bit.
• One-sided irregularity or stiffness that wasn't there before.

Trying out a new bit step by step

Give a new bit at least 3 to 4 weeks before passing judgement. During the first week, ride on purely voluntary contact without pushing too much from behind, so the horse can get used to the new feel. After each training session, write a brief note: how did the horse respond to rein aids, was there mouth activity, was there tension? With the training log function in EquiSight you can keep track of these observations clearly. If you see no improvement after 4 weeks, consult a certified bit fitter — in the Netherlands there are approximately 80 KNHS-recognised specialists.

When should you consult a specialist?

A bit fitter looks beyond just the mouth size. They assess the oral anatomy (tongue thickness, bar spread, palate height), the riding style and the horse's level. This is especially recommended for horses with a fleshy or thick tongue, for horses that continue to show prolonged resistance, and for horses competing at a higher level. Use EquiCoach in the app to ask more targeted questions during the consultation: type in your observations and receive concrete guidance to steer the conversation with the specialist.