The Science of Horse Racing: Bits

September 15th, 2023

Controlling a horse’s head is an important part of riding, especially when going racehorse speeds. Trainers have a variety of bits at their disposal, with each fulfilling a specific function based on what the horse needs. Learning more about those more commonly used on the racetrack can clue fans into the personalities of the horses they see. From a simple snaffle to a Norton, the right bit is just as important as the saddle and the blinkers you see on your favorite Thoroughbred. 

What Is a Bit?

A bit is part of the tack that enables riders to have control over their horses in all settings, from the racetrack to the show ring. When you picture a bit, you may think of it as just the part that goes in the mouth, called the mullen, but it also includes other components like shanks, rings, and cheekpads, each coming in different forms depending on the type of bit. This connects to the bridle and reins and rests in the part of a horse’s mouth that does not have teeth, the area between the front teeth, which crops grass, and the back teeth, which grinds food. Resting on the tongue and hard palate, the bit helps cue a horse as to what speed and direction the rider wants. 

Archaeological history tells us that the horse was domesticated around 6,000 years ago with early riders likely using some sort of bitless bridle made of leather or rope to control their mounts. Bits come along later, usually composed of wood, rope, or bone, with bronze versions arriving 1300 BCE. In the modern era, nickel was the preferred metal for bits until stainless steel came along in the first half of the 20th century. Rubber and plastic bits are also an option depending on the purpose and the horse. 

Each equine discipline has bits that fit with their activities, helping riders work with their mounts to jump, rack, or gallop. On the racetrack, you will see several kinds of bits, each helping both rider and trainer get what they need from their horses.

Snaffles and Rings 

The most commonly used bit around racetracks is the snaffle. Snaffles consist of either a bar or multiple pieces linked together, which are directly connected to the bridle and reins and use pressure on the mouth to communicate with the horse. The pressure that the horse feels is proportional with the pressure that the rider puts on the reins. 

Snaffles come in different forms, with the variety coming in the pieces attached to the mullen. For example, an eggbutt snaffle, generally used for younger or greener horses, have oval rings attached, which lie flat against the horse’s cheeks. These rest securely in the mouth and prevent the bit from sliding back and forth and pinching the lips. 

Similar to the eggbutt is the D-ring, which is the snaffle bit you will see most often around the racetrack. Rather than an oval-shaped ring, the rings on this one are shaped like a capital "D," with the straight portion of the ring resting against the mouth. D-rings tend to be gentler on the horse and are good for horses that might have sensitive mouths, and they do not require the same level of control offered by the eggbutt or another type of snaffle called the ring bit.

The ring bit, especially the Dexter version, is another common bit on the racetrack. This type has two mouthpieces, one that goes inside the mouth and another that encircles the lower jaw. The oral portion can be metal, plastic, or rubber, but the other part is metal. This bit is generally used on stronger horses since it can add stopping power for the rider but also more leverage for steering with that ring around the lower jaw. This is a good choice for horses that are inclined to bear out or lug in.

This look at basic bits for racehorses inspires another discussion about this part of the tack necessary for their jobs. Over the sport’s history, some familiar names have required a little more creativity to get them to perform at their very best.

Champions and Their Bits

Photos of Citation, the eighth Triple Crown winner, show him sporting a rather unique bridle, one that uses both mouth and facial pressure to control him. Known for his tenacity on the racetrack, he could be strong-willed, and trainer Jimmy Jones knew he would need more than the usual bit to work with that personality. Jones outfitted his start with a Norton bit, a double snaffle attached to the bridle with both cheek pieces and a y-band noseband that runs from the bridle’s headpiece. This setup worked best for strong horses with experienced riders, which made it the right fit for both Citation and his regular rider Eddie Arcaro.

Kentucky Derby and Preakness winner Funny Cide used a Haughton bit. Similar to the Dexter version of the ring bit, this has a three-sided bar beneath the lower jaw rather than a ring and can have a leather-covered mullen for the mouth. Because he had a small and sensitive mouth, the Haughton enabled Funny Cide’s rider to keep him from bearing out while accommodating his tender mouth. Similarly, the regulator bit that trainer Steve Asmussen used for Curlin also had a leather-covered mullen, but with two rings on each side, giving the rider more leverage to keep a horse traveling straight. 

Horses at every level and in all disciplines should have the right bit for the tasks at hand. This important piece of the puzzle might require some trial and error to find what works, but once a trainer hones in on the one that works best, they can help their charges make the most of their talents and abilities