Curb Bits Explained
Curb bits are suited for more mature horse (4 to 5 years old) with the capacity of accepting more pressure from the bit and more pressure on their face.
Because they were used primarily for working horses and cowboys who needed one hand free for roping, shooting, and hat-tipping, they are designed for one-handed riding as opposed to the two-handed style of the snaffle bit. A curb bit will put pressure on the mouth, the poll, and on the chin through the curb strap or chain.
They generally have a solid mouthpiece as opposed to the jointed mouthpiece of a snaffle bit. In the conventional curb bit, the butt of the mouthpiece is set solidly into the cheeks, and the cheeks do not work independent of each other.
The basic mechanics of a fixed-cheek curb bit make it a poor turning bit but a great stopper. However, with a little too much pull, it may cause a horse to throw its head out of the turn or up to escape the curb action.
They have a port mouth (bump of various size in the middle), which offers more tongue relief than a broken-mouth snaffle. Rather, when the curb is engaged (the mouthpiece is squeezed down onto the mouth bars by the vice action), they put more contact-pressure on the bars. They can also pressure the roof of the horse’s mouth (palate) if the port is over about 2″ high or higher than the horse’s mouth can take. (Palate pressure is appropriate only for horses with very advanced training who are prepared for it).
The horse’s tongue makes a large pillow in his mouth, filling the mouth from lower jaw to palate when at rest. The curb bit sits gently across this pillow, held off the bars by the plump pressure of the tongue up against the palate. A horse learns quickly how to comfortably “carry” the bit in that position. The port gives relief to the tongue when the curb pressure forces the bit down onto the bars of the horse’s mouth. It allows the tongue some place to go under pressure, slipping it up into the port space. A low port gives less relief. A high port gives more tongue relief, but with the tongue high up into the port the bit sits lower on the sides (bars) and so reaches the bars of the mouth more quickly to transmit a stronger signal. That is, a high port bit has less “pillow” supporting it on the sides. A low port bit pressures the tongue more.
Curb Bits have shanks that add leverage to the reins, enhancing the chin pressure that magnifies the bar pressure in the horse’s mouth (see Bars) and engages the poll strap for pressure on the poll. Leverage magnifies the pressure from the rider’s hands to the horse’s face, making signals less obvious to the on-looker but more powerful to the horse. (see Leverage)
As the reins pull back toward the horse’s chest, the shanks rotate back and up until the curb strap stops the rotation. The pressure tightens the curb strap under the chin – effectively putting the horse’s lower jaw in a vise-like grip between the mouthpiece and the curb strap. The grip pulls the bit down onto the bars of the mouth. (The rotation also lifts the port up into the palate if the port is high enough.) When the curb action is engaged, the the nerves of the chin are more sensitive than the bars and tongue. Therefore, care should be taken to use a leveraged curb bit lightly, or the horse’s head will fly up in an effort to avoid the curb strap instead of collecting and keeping his head down where you want it.
The time it takes between the rein cue and the shank moving far enough to engage the curb strap is known as the “signal” time. If the shanks are adjusted at a proper angle (usually about 45 degrees), the horse will have time to realize that the shank is moving and prepare for the action before the bit is actually engaged. If properly trained, he will anticipate the request the moment the rider picks up the reins, and only leg or body aids will be needed to direct his movement. (See Signal)
A bit with a looser curb and a longer shank will have a longer “signal” time because there is more distance from reins to curb strap engagement – giving the horse longer to compute the next step. Additionally, when a bit is balanced so that its rein loops hang a little forward of center when not engaged by the reins, it takes just that fraction of a second longer for the reins to take up the slack, which lengthens the signal time. A bit balanced this way is an advantage for quick release of pressure and reliable neutral position. A bit is “balanced” if, when the reins are dropped, the bit immediately swings forward to its “home” or vertical position and releases the pressure. (see Release Training)
A long signal time is desirable. Short signal time is to be used only by the most experienced riders. Quick Release is critical for all training.
A higher port (see diagram above) gives a horse more room for his tongue (tongue relief). When relaxed and when the bit is pressured down onto his bars, he can slip his tongue up into the space avoiding most of the pressure in the center tongue. However, it imparts more pressure directly to the bars and/or palate of the horse. Additionally, the longer the shank, the more pressure can be brought to bear on the chin and bars. (see Bit Leverage)
There are hybrid bits with loose cheeks and solid mouthpieces. The bit at the left has both loose shanks and a solid mouthpiece – not quite the usual “cowboy” curb bit but a good transition bit. The low, wide port offers more room for the tongue of a horse who is ready to leave his broken-mouth bit (with deeper tongue pressure) and start to learn how to wear his solid-mouth bit. If the Dee rein is used, this bit rolls forward for tongue pressure but has no leverage at all. If the lower rein loop is used, it rolls forward with rein pressure, pressing the port down on the center of the tongue AND pressing on the bars as curb action and leverage is added. The loose-cheek offers the same efficient lateral pull as a Dee snaffle for the horse in transition.
A port of 1.5″ -2″ is usually sufficient to make a horse comfortable and avoid any potential of palate pressure. Ports 3″-4″ start to get into his palate. When English riders (or novice riders) see this type of bit they immediately wince and exclaim at its “cruelty”. However, once understood, this bit has a place in Western riding.
Because Western horses perform with very little bit contact, this bit is designed to keep a horse’s head on the vertical with no cues from the rider whatsoever.
Notice that this bit is not really a “curb” bit, as it incorporates no curb strap. There is no curb action at all. It is commonly called a spade bit.
If properly balanced, when the rider is not “on the reins”, this bit will rest comfortably in a horse’s mouth, allowing him a lot of tongue relief and affording no other pressure – provided his head is in the proper position. If he raises his head, the bit tips forward (by itself), contacting the palate, which reminds him to lower his face back to the “sweet spot” where the spoon top is again comfortably resting without touching his palate. The horse has total control of the position of the bit.
Needless to say, this bit is for well trained horses that need very little rein contact from the rider and experienced riders who do not “ride the reins”, as jerking or pulling back on this bit can cause palate damage.
The term Grazing Bit was developed when cowboys needed a bit that their horse could use for grazing in their bridle. It has swept-back shanks that mitigate the leverage – softening it. However, the fact that the shanks are bent back shortens the signal time. They are already several degrees into the 45 degree angle that adds time to your reins. Reins engage more quickly and should be used by intermediate riders whose aids are well developed.
While this Quick Stop with Rope Noseband has no mouthpiece, it certainly has leveraged cheeks that apply pressure to the chin bar, which is forced up onto the sensitive, non-muscled area of the jaw bone. The cheeks magnify the pressure to encourage a very fast whoa. Not for a novice rider or trainer, as it can be very severe.
Snaffle Bit to Curb Reverse
When a horse changes from a snaffle bit to a curb bit and is asked to change his direction using neck reining techniques, the bit will be very confusing. A significant amount of training using simultaneous rein cues will be necessary to avoid your horse “reversing” the cues. (When the reins on the neck side of a curb bit are laid against the neck to cue the turn, that rein is shortened – actually feeling to the horse like he should turn into the short rein.) That “reversing” effect must be overcome if you want to move to a one-handed curb bit.
Loose-shanked or loose-cheek snaffles, loose-cheek Argentine or loose-cheek curb bits retain independent lateral movement on each side of the face. They are sometimes used as a bridge to the curb bit, although they have their drawbacks too.
What is the “BEST” curb bit for an intermediate rider on an experienced horse? A fixed-shank curb bit is more forgiving of uneven reins, as its effect is felt multilaterally (on both sides of the face). A medium port mouth will give tongue relief without acting on the palate. An “S” shaped shank usually balances to release quickly. (see Release Training) The same shanks offer more leverage but less subtlety of signal.
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