How to choose a bit for your horse and common problems

How to measure your horse for a bit

Use a piece of smooth round wood, e.g. a wooden spoon handle or piece of doweling, and two rein stops (rubber bands can be used but are slightly less accurate.) Put the wooden rod into your horses mouth, so that it just lifts the corners of his lips into no more than 2 wrinkles, and push the rein stops up to touch his lips on either side. Remove the wood, and measure the gap from the outside of the rein stops to give the correct bit size including the right amount of clearance for the bit. If you are between sizes (e.g. 5 1/4"), it is normally better to choose the smaller of the two sizes (e.g. 5") unless opting for a loose ring bit when it can be advantageous to go slightly large to prevent pinching.

Which bit should I buy for my horse?

It can be a challenge to find the right bit for your horse, particularly if they are new to you and rider and horse are still getting to know each other. The eye of a sympathetic and knowledgeable trainer is often a tremendous help as they are able to asses horse and rider as a partnership and spot the signs the horse is displaying and suggest a good bit to try. There are however some conformational pointers you can look for that help to suggest what type of bit may suit your horse and narrow the search. Certain breeds of horse can be prone to certain mouth shapes for example cob types often have large tongues which leave little room for a thick bit to sit comfortably in. Using a thick bit on a horse with a large tongue will often result in the horse opening their mouth, sticking their tongue out or trying to get the tongue over the bit- anything to relive the pressure. Often, a flash will then be used to stop this behaviour, but a bi like cough mixture this relieves the symptoms but is not actually solving the problem! Thin bits are often considered to be severe, but if a horse has a thick tongue a thinner bit will allow the horse to relax and swallow where a thicker ‘kind’ bit would not, presuming the rider is competent enough not to need the reins for support the thin bit is actually far kinder to the horse.
When examining your horses mouth, have a look carefully at the shape and anything that is different or unusual as even little things can potentially make a big difference to the way a horse will react in a bit. The table below outlines some of the common observations in a horses mouth, the bitting implications and possible solutions.

Mouth observation: Possible bitting problems: Bitting suggestions:
The horses tongue bulges out from the bit space in his teeth when the lip is lifted. Often an indication of a large tongue. This means the horse potentially does not have a lot of space to comfortably hold a bit and restriction in swallowing could be a problem. A thinner than average bit is better for horses with a large tongue, and often a gently ported or double jointed bit will give more tongue space and allow the horse to swallow more easily.
The horses front teeth don’t meet properly, meaning the molars do not end squarely either. Often a horse has an overshot (also known as a parrot mouth) or undershot jaw. This can result in the molars not meeting squarely which can lead to sharp hooks developing far sooner than usual which can lead to bitting problems. Any bit is suitable for a horse with slightly unusual jaw conformation, but you may find the horse prefers a thinner bit positioned fractionally lower than usual so as not to contact the teeth unduly.
The roof of the horses mouth is obvious and pushes down into the horses tongue/ A low palette is common among a lot of breeds including Arabs and TB’s and their crosses. Bits that exert pressure on this sensitive part of the mouth can cause discomfort. A single joint should be avoided as this can jab the roof of the mouth causing the horse to toss their head to try and escape the action. A double joint (ideally a lozenge centre if the horse also has a large tongue) or gentle mullen mouth and definitely on the thinner side will be the most suitable.
The bar of the horses jaw (where the bit sits) is sore, bruised or puffy. Horses with sore bars need a bit that is not going to exert pressure on the bars of their mouth. Mullen mouthpieces, or combination style bits that help to remove pressure from the bars are kindest. The bit should ideally not be too thin to increase the bearing surface of the mouthpiece. In extreme cases it may even be necessary to use a bitless (hackamore) bridle for a time until the horse is less sensitive.
The horses lips bulge out when the bit is in his mouth. Fleshy lips are common particularly with heavier breeds, and can be prone to damage from tight bits. Any bit is potentially suitable for a horse with fleshy lips, but generally a thinner bi is less likely to cause a split in the corner (as long as the rider is competent) as it will not stretch the skin as much. It is important to allow enough room for the lips particularly with lose ring bits to prevent pinching.
Tongue shows red or swollen areas/soreness or signs of an old injury. A sore tongue can cause problems for the horse as contact with the bit can be very uncomfortable. A soft, mild bit possibly with a rubber or plastic covered mouthpiece may help, and possibly even a single jointed bit if the palette with allow to relieve pressure from the tongue. In extreme cases it may even be necessary to use a bitless (hackamore) bridle for a time until the horse is less sensitive.
The presence of wolf teeth Wolf teeth are small molars that can appear in front of the molars in the area in which the bit sits. Wolf teeth can cause bitting problems, as they can catch on the bit. Some horses don’t seem to mind, but often a softer plastic or rubber covered bit can help prevent the horse from being over sensitive when bridled. Positioning the bit slightly lower than usual can also help.
Sore areas in the corner of the horses mouth. Split lips can happen for a number of reasons, most commonly lack of salivation leading to dryness, bit too thick causing positioned too high in the horses mouth causing stretching/splitting. Bits made from stainless steel are often responsible for sptil lips if th horse does not saivate in them. Using a mouthpiece made from a copper or sweet iron type metal will give your horse a taste and encourage him to accept and mouth the bit. A thinner bit positioned carefully so it is not too high often also very beneficial.
Horse putting their head down/between their legs Pulling and yanking Refusing to soften down onto the bit
Horse throwing their head up Coming behind the bit Head shaking, tongue stuck out

Common problems and possible biting solutions

Size chart for a general foot size comparison, please refer to the manufacturer charts for precise sizes, widths and lengths of individual styles.

Symptom Possible cause Possible Remedy:
Head tossing/shaking, or nodding up and down Sore back, incorrectly fitting saddle, wolf teeth knocking on the bit, bit placed too low/ too high. Check the saddle fit and the horses back, ensure young horses are given frequent breaks when asking them to work for you. Check the height of the bit in the horses mouth and try adjusting it very slightly higher or lower than normal to see if the horse is happier.
Open mouth, sometimes with tongue sticking out or putting the tongue over the bit Often a symptom of a large tongue/small mouth- single jointed bits should usually be avoided, as should thick bits. Recommended: The peewee bit often works very well for horses that put their tongue over the bit or stick it out as it is unobtrusive. The Sprenger WH ultra is a dressage legal bit, the 16mm in particular is very successful for horses that resent tongue pressure and try to draw their tongue out from underneath it. A flash is not the best answer for a horse that opens its mouth, as all that does is cover up the symptoms, solve the problem and help the horse to accept the bit.
Also suitable:
Most thinner, double jointed (French link) style bits that do not cause tongue pressure. A fine mullen or Cambridge mouth may also suit.
Refusal to soften down onto the bit, poking the nose Usually seen in young or lazy horses. Can be the result of too thick/mild a bit. The key is finding the right bit in conjunction with a lot of turns and transitions. Usually a thinner, either double jointed style bit with a hanging cheek works well. The Myler combination bits, especially the 30 04 can be invaluable for education horses in the right hands with corrrect schooling.
Horse putting their head down/between their legs. Often seen when the horse is in an exciting situation and is a common evasion with horses prone to being on the forehand. The ideal bit for this is the Myler correctional ported barrel bit. The 33 42 combination version is excellent for strong horses that try to run away with you with their head down/out/tucked in. Pelhams, kimblewicks and other conventional curbed bits should be avoided as they all encourage the horse to tuck under in avoidance of the action of the curb. True gag bits can be useful for horses that put their heads down, but this can lead to a further evasion of the horse tossing his head in some cases.
Pulling and yanking Attempting to grab the bit between the teeth, trying to yank the reins from the riders hands are all evasions that horses often display when excited. The peewee is a very useful bit for horses that are not overly strong, but yank in a snaffle. Traditionally Waterford bits have been used to help prevent leaning and pulling but do need to be used with sympathetic hands. Sometimes swapping the horse into it a thinner version of his bit (if he otherwise goes well in it and it is fairly thick) will be enough to encourage him to give the bit a little more respect.
coming behind the bit Horse will not take the bit, rider feels like there is no contact at the end of the rein. This can be seen in horses that have been over bitted and are afraid of the contact, or sometimes in young horses new to being bitted and ridden. A very mild and sympathetic bit is often called for just for a short period, for example a loose ring flexible plastic bit. This should encourage the horse to take the contact. Once this has been established, move the hrse into a sympathetic bit such as a Sprenger KK ultra 16mm to keep his confidence but further his training.
Leaning on the bit Horse sets his neck and bears down on the bit. Often seem in horses on the forehand as an evasion, especially in exciting situations. The Waterford is the most well known bit for this type of evasion, and can help to prevent leaning but should be used sympathetically. Myler combination bits often work well, the 30 04 being popular or the 30 42 if the horse puts his head down whilst pulling.
Head right up high, stargazing or being thrown right up high Check the horses back and saddle fit as this can be a way for the horse to relieve a sore back temporarily. Often seen in arab or hot blooded horses. Once a sore back and saddle fit have been eliminated, the Myler narrow ported barrel high is ideally suited to this problem. The 33 43 combination bit has great success at encouraging a more rounded outline and preventing a high head carriage and helps to school horses out of the habit. Traditionally, curbed bits such as a Kimblewick or Pelham can be used, but these can sometime lead to the horse bearing down instead.


Not the tasty chocolate chip kind, but important for you to know - we use cookies to offer you the best experience possible when shopping with us.
Continue to browse if you're happy with our Privacy & Cookie Policy.