What is the gentlest bit for a horse?

The University of Florida's Dr. E. L. Johnson writes that, regardless of the bit selected, what generally makes it good or bad is the hands using it, and that in most instances the problems perceived as coming from the wrong bit are in reality training problems. The University of Georgia's Bits 101 bulletin (Kylee Jo Duberstein, full review February 2024) says the rider's hands are the most important factor in communicating with the horse.

So this page does not crown a winner, and we don't rank bits. What it does is lay out the things those sources say change how a bit feels to the horse, and who to ask when yours is unhappy in his mouth. If you want the designs themselves described, see Snaffle, pelham, gag or hackamore; for width, What size bit does my horse need?.

Dr. Johnson says a mouthpiece can be mild in its action and pressure (a soft bit) or severe (a harsh or hard bit), with many gradations between the extremes. He writes that moderate bits are probably the best choice for most people and horses, and that harsher bits should be reserved for people who know how and when to use them. Georgia's bulletin says inexperienced riders or horses should be equipped with softer, less severe bits, because inexperienced riders lack the hand control to use more severe bits effectively.

Both also say softer is not automatically better. Dr. Johnson says soft bits can be problematic because it is easy to teach a horse to pull against and evade them, and that this is a mistake many people make trying to be kind to their horse. Georgia's bulletin says a moderate bit is probably best for most people and horses, and that the rider must experiment to find which bit a particular horse performs better in.

The table lists the factors the sources name. Each one is described as they put it, so you can see why 'gentlest' has no single answer.

Georgia's bulletin says a larger diameter mouthpiece diffuses the pressure on the tongue and bars. Dr. Johnson adds that soft bits are usually large in diameter, and that many young horses do not have enough room in their mouth to carry one comfortably, which he says can lead to annoying habits. Utah State's snaffle fact sheet makes a related point: a mouthpiece that is too thick can stop the horse from closing his mouth without squeezing his tongue.

Makers describe their own materials in gentle terms, and you'll see those words on product pages. Happy Mouth describes its polymer mouthpiece as gentler than metal, with an apple scent meant to encourage acceptance; see our Happy Mouth page. Herm Sprenger describes its Sensogan alloy as encouraging salivation and a delicate connection; see our Herm Sprenger page. Those are the makers' own descriptions, not independent tests, and no source we read ranks materials against each other. For what each metal and rubber does, our Barn Talk on mouthpiece materials has the details.

Dr. Johnson says the key to identifying a snaffle is that it works off direct pull with no leverage, whether or not the mouthpiece is jointed. Utah State says even bits considered mild can become severe: pulling both reins at once on a broken-mouth snaffle can fold the mouthpiece, which makes a mild bit severe, and it recommends soft hands and training.

On going bitless, Horse & Hound's bitting expert, Tricia Nassau-Williams, writes that bitless bridles can apply a large amount of force to the soft and sensitive facial structures, so they are not necessarily a softer option than a bit. She advises great care in selection and fitting, and being mindful of restrictions in some competition rule books. For how the designs differ, see Snaffle, pelham, gag or hackamore; for what the cheek does, Loose ring, eggbutt or D-ring.

Utah State's fact sheet says a solid mouthpiece such as a mullen mouth gives the tongue relief and does not fold, while a broken mouthpiece can fold if both reins are pulled at once. Dr. Johnson says bits with broken mouthpieces or swivel cheeks are slower acting and give the horse what amounts to a preparatory signal. Georgia's bulletin says some horses with shallow palates are more comfortable in bits that conform around their mouth, and that a port taller than about 2 inches may touch the roof of the mouth, depending on how the curb strap is adjusted.

The cheek matters as well. Utah State says a full-cheek snaffle keeps the bit from being pulled through the mouth, and that loose-ring snaffles need mouth guards to prevent pinched lips and are not a first choice for young horses. Dr. Johnson says full-cheek bits should always be used with bit keepers for safety concerns for both the horse and rider. Our cheek-piece explainer goes through those designs.

Utah State says the mouthpiece should be 1/8 to 1/4 inch wider on each side than the horse's mouth. On a loose rein it says the bit should hang at the corners of the mouth without wrinkling them, and the horse should not look as if he's "smiling", since that puts tension on tender tissue. Dr. Johnson gives common widths: 5 inches is standard and the most common, ponies generally take 4 1/2, and bits designed for Arabians are 4 3/4; wider mouths take 5 1/2, 6 or more.

Those are extension rules of thumb, not a substitute for someone looking at your horse. Our Barn Talk on bit size covers measuring in full. If the fit looks right and he is still unhappy, that is the moment to ask a veterinarian or equine dentist to check his mouth, which is where the next section picks up.

Utah State's snaffle fact sheet (Evans and Barnett, 2007) says the horse's teeth should be evaluated prior to bitting: points and hooks should be filed and wolf teeth removed, because bit pressure on a wolf tooth causes gum discomfort and its sharp point can pinch the tongue. It says horses with wolf teeth or other dental problems may show signs of irritation, including resisting the bit, evading it, tossing the head and mouthing the bit.

That is a job for your veterinarian or an equine dentist, not for a new mouthpiece. Georgia's bulletin, for its part, notes that many problems perceived as coming from the wrong bit are really training problems, which is a job for a trainer. If your horse is fussing, the sources we read point to the same short list: a mouth and teeth check, a look at the fit (width and thickness, per the table), and a trainer who can watch you ride.

One rider describes the order of events in a review: conditioning and behavior work first, and a different bit as the last piece, not the whole answer.

Georgia's bulletin says the rider must experiment to find which bit a particular horse performs better in, and that it is important to experiment with bit selection. Dr. Johnson says that in a training situation or for pleasure riding the choice doesn't need to consider anything other than what is best for the horse and rider, but notes that breed and show associations may restrict which bits are allowed, and that tradition can lead to a horse being bitted with a bit that isn't the best choice.

A practical order, built from what the sources say: have the vet or equine dentist look at his teeth and mouth; get the width right (Dr. Johnson lists 5 inches as the most common standard width, 4 1/2 for ponies and 4 3/4 for Arabians, and Utah State gives the 1/8 to 1/4 inch rule); ask a trainer to watch you ride; then try changes with your trainer's guidance. If you ride in a show, check the rule book first: Is this bit legal for dressage? and Which bits are legal in the hunters and equitation? explain how to read it. You can browse the horse bits we carry, and the maker pages for Nathe, JP Korsteel and Korsteel describe each design in the makers' words.