Horses generally prefer the snaffle because they don’t like getting poked in the hard palate. Bits with ports, such as kimberwicks or curbs, work by applying pressure to the hard palate.
Decades of research have proven to Dr. Hilary Clayton, of Michigan State University, that “one of the things horses really dislike is when the bit is pushing against the roof of the mouth.”
Horses with small oral cavities or hard palates close to their tongues often don’t like single-jointed snaffles because the joint presses against the palate when you apply pressure to the reins, and that causes discomfort. These horses usually prefer either a straight-bar or a double-jointed snaffle, which riders have often tried because they thought they were “less severe” than a single-jointed snaffle. Really, they’re just more comfortable.
But picking the right-sized plate to use on a double-jointed snaffle is, once again, a matter of trial and error, because it depends on the size and shape of your horse’s mouth and how he uses his tongue to accept or avoid the bit. Should you use a bean that doesn’t roll, a bean that does roll, a French link, or a Dr. Bristol?
X-rays have shown Clayton that the distance between the bars on each side of the mouth is only 2 to 2.5 inches. So, if the plate is wide, the joints on a wide link or plate could put the joints right on top of the bars, “which would be quite painful,” she said.
That’s why Clayton prefers double-jointed bits with narrow plates, like the KK bits. The KK plates are also rotated 45 degrees so that they lie flat on the tongue, not digging into the tongue on an angle. “They’ve accommodated the way the bit sits on the tongue, so it’s more comfortable and, therefore, more effective,” she said.
And that’s why some horses really like the KK Ultra, many of the Myler bits or straight-bar snaffles. They don’t touch the roof of the mouth, and they’re more comfortable on the tongue and the bars.
(The KK Ultra is one of dozens of bits manufactured by the German company Herm Sprenger. The KK bits are made of a metal called Aurigan, a patented nickel-free alloy made of copper, silicon and zinc. The KK bits range in price from $99 to more than $250, but replicas of the design, made without Aurigan, can be purchased for $60 or much less, usually in the same catalogs. )