Bit Severity Chart: Choose a Fairer Feel

A bit severity chart can look simple: one end is labelled mild, the other severe, and every mouthpiece seems to fall somewhere in between. But a chart cannot feel what your horse feels. In western riding, where a good stop, soft face and willing turn matter, the right bit is less about finding the strongest option and more about creating a clear, fair conversation.

A horse that braces, opens its mouth, throws its head or becomes dull to the rein is not always telling you it needs more bit. It may be telling you the fit is wrong, the signal is unclear, its teeth need attention, or the rider’s hands are asking too much. That is why bit choice deserves more thought than a single severity rating.

What a bit severity chart can and cannot tell you

A bit severity chart is useful as a rough comparison tool. It helps riders understand the general differences between a smooth snaffle, a twisted wire mouthpiece, a short-shank curb and a longer-shank leverage bit. Used well, it can stop you from treating every bit as though it works the same way.

What it cannot do is give one fixed answer for every horse and rider. The same bit can feel entirely different depending on rein tension, shank length, mouthpiece shape, adjustment and the hands holding the reins. A well-fitted curb used with quiet, educated hands may be less confronting than a supposedly mild bit ridden with constant pressure.

Charts also tend to miss the horse in front of you. A quiet gelding with a broad tongue may resent a thick, single-jointed mouthpiece, while another horse may settle beautifully in it. A horse with a low palate may find a high port uncomfortable. Severity is not a product label alone. It is the result of design, fit and use.

How bit severity is really created

When you read a bit severity chart, look beyond the name of the bit. Several features work together to change the pressure a horse receives.

Mouthpiece shape and texture

A smooth, wider mouthpiece usually distributes pressure over a greater area than a narrow or twisted mouthpiece. That does not make every smooth mouthpiece automatically gentle, but it is generally less concentrated than a thin twisted wire or multi-link design.

Single-jointed mouthpieces can create a nutcracker action when both reins are engaged. On some horses, this can lift into the palate and press on the bars. A double-jointed mouthpiece often follows the mouth more independently, though the centre link and overall thickness still matter. A mullen mouth applies more even pressure across the tongue and bars, while a port creates room for the tongue to varying degrees.

Ports need honest assessment. A low, swept port may offer tongue relief without becoming aggressive. A tall port, particularly paired with leverage and a curb strap, can apply significant pressure if the reins are taken up firmly. The more moving parts, edges, twists and narrow contact points a mouthpiece has, the more carefully it needs to be used.

Leverage and shank length

A snaffle works through direct pressure: the rider takes one kilogram of rein pressure, and the horse generally feels one kilogram at the mouth. A curb bit uses leverage. The shanks rotate, the mouthpiece acts on the bars and tongue, and the curb strap comes into play under the jaw.

Longer shanks generally increase leverage and slow the signal. Shorter shanks offer less leverage and a quicker feel. But shank length is only part of the picture. The purchase - the section above the mouthpiece - affects how soon the curb strap engages, while the angle and design of the shank influence how the bit rotates.

This is why a short-shank curb is not necessarily mild, and a long-shank curb is not necessarily harsh in every set of hands. The rider’s rein contact is still the deciding factor.

Curb strap adjustment

On a leverage bit, the curb strap is not an optional accessory. It controls the bit’s rotation and changes when pressure comes on the horse’s chin groove. If it is too loose, the shank can rotate excessively before the strap engages, allowing the mouthpiece to move farther than intended. If it is too tight, the horse receives chin pressure almost immediately.

As a practical starting point, allow room for about two fingers between the curb strap and the horse’s jaw when the bit is at rest. Then check how much the shank rotates before the strap starts to work. A good set-up should give a clear signal without collapsing straight into pressure.

Bit fit in the horse’s mouth

A bit should sit comfortably without pinching the lips or sliding so far side to side that it loses stability. Too narrow can rub and pinch. Too wide can move excessively and make the rein aid vague.

Thickness is not always kinder. Horses with fleshy tongues or limited room between the tongue and palate can find a thick mouthpiece crowded. Look at the horse’s mouth, not just the catalogue description. Dental comfort matters too. Sharp teeth, wolf teeth, ulcers and mouth injuries can turn an acceptable bit into a source of real discomfort, so involve an equine dental professional if behaviour changes suddenly.

Matching the bit to the job

Western disciplines ask different questions of a horse. A young horse being started or brought along in foundational work generally benefits from a direct, uncomplicated feel. Many riders begin schooling in a suitable snaffle or a mild transition bit, focusing on bend, softness, stop and response to the seat before expecting a horse to carry itself in a curb.

A finished reining horse may work in a shank bit with loose rein and neck rein cues because the training is there to support it. A ranch horse may need a practical, reliable bit for gates, stock work and long days. A rope horse may need to rate a steer, face with confidence and stay responsive when the job gets fast. None of that means a harder mouthpiece is the answer. It means the bit needs to suit the horse’s education, sensitivity and task.

If you are moving from a snaffle into a curb, make the change for a training reason, not because your current bit has stopped working. A horse that pulls through a bit may be unbalanced, anxious, sore, anticipating the stop or simply not responsive to the rider’s body cues. More leverage can mask that issue for a ride or two, but it rarely fixes it.

Signs the bit may be too much - or not right

Watch your horse before, during and after you ride. Excessive gaping, tongue movement, head tossing, rooting, leaning, curling behind the contact and rushing away from the rein all deserve attention. One sign alone does not diagnose the problem. Flies, saddle fit, teeth, rider balance and training pressure can all contribute.

The better question is whether the horse can stay relaxed and answer a light cue. A suitable bit allows the horse to seek a comfortable place, respond without fear and return to softness when the rein is released. It should not require constant holding.

Also be honest about your own hands. In the heat of a run, a hard stop or a tough day working cattle, every bit feels stronger. If you know your hands can get busy when adrenaline rises, choose a set-up that gives you a margin for error and keep schooling the response you want at home.

Use the chart, then trust the horse

Think of the bit severity chart as a map, not a rulebook. Compare the mouthpiece, leverage and likely pressure points, then make a sensible choice for your horse’s mouth, training stage and work. Check the fit carefully, adjust the curb strap correctly and ride with release as your reward.

Good western tack should help a horse do its job with confidence, whether that job is running a pattern, roping in the box, checking fences or carrying you down the track. The fairest bit is the one that lets your horse understand you with the lightest, clearest cue you can give.