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.
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 tongue relief
but can also pressure the roof of the horse’s mouth (palate) if the port is over 2″ high.
(Palate pressure is appropriate only for horses with advanced training who are prepared
for it).
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 it also reaches the bars more quickly and transmits a stronger signal.
Curb Bits have shanks that add leverage to the reins, enhancing the chin pressure that
magnifies the bar pressure in the horse’s mouth 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.
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 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.
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. 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.
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.
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 swivel that gives time to your reins.
They engage more quickly and should be used by intermediate riders whose aids are
well developed.
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 fixedshank 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. The same shanks
offer more leverage but less subtlety of signal.