Home » Tack and Equipment

The Trouble with Tom Thumb

18 August 2011 3 Comments

The Trouble with Tom Thumb
By: Mark Rashid

As a trainer and clinician I am always being asked a variety of horse-related questions. I think the single most common one asked, however, is “what kind of bit should I use on my horse?”

In my situation, if I need to do any training on the horse whatsoever, I use a simple full-cheek snaffle bit. If the horse is well-trained and responsive, he stops, backs, and neck reins all on a light cue, then I use a curb or grazing bit. These are the only types of bits that I use on a regular basis, and are the only ones that I feel comfortable recommending.

There is one bit that I never recommend, however, and in fact do my best to try to talk people out of using, particularly if they are experiencing problems with their horses – problems such as unresponsiveness while stopping, backing, or turning, or even more severe problems like head tossing, shaking their heads, or rearing. The bit that I am talking about, and which is often the source of such problems, is the Tom Thumb snaffle.

Shown from left to right are a full cheek snaffle bit, the Tom Thumb bit, and a grazing type curb bit with a leather curb strap.

Transition Bit
The Tom Thumb snaffle was originally designed as a transition bit that was to be used in Western training. When a green horse was far enough along that perhaps a training snaffle was no longer necessary, but not far enough along to be moved into a curb bit, the Tom Thumb would be used. This would be great, if in fact, it made the transition simple and easy. Unfortunately, it doesn’t. The truth of the matter is that, due to its design, it could possibly be considered one of the worst bits that somebody could use at a highly critical time in a young horse’s training.

The Tom Thumb is commonly termed a snaffle bit because its mouthpiece is broken, or hinged, which is a trademark common to the true snaffle bits. That is where the similarities end. On a true snaffle bit, the reins are attached to a relatively small, swiveling ring which could be considered a working part of the mouthpiece itself. When the rein is pulled, as you would do when asking the horse to turn, the ring that the rein is attached to moves completely away from the horse’s mouth. The mouthpiece itself slides in the same direction, which causes the ring on the opposite side of the horse’s mouth to apply pressure on that side. Because the horse is taught to go away from pressure, it then makes sense that if you are pulling to the left, and thre pressure from the bit is on the right side of his mouth, he will naturally turn his head to the left. This is the simple principle that is commonly referred to as direct reining, or “plow reining”. It is also a principle that is almost impossible to perform properly with the Tom Thumb, due to its design.

Unlike a true snaffle bit, the Tom Thumb has shanks similar to the ones found on a solid curb bit. It is to the bottom of these shanks that the reins are attached. The headstall is attached to the top of the shank, as is some type of curb strap which fits around the bottom of the horse’s jaw, in the chin area. These shanks swivel and are attached to the bit’s mouthpiece.

It is that one flaw in the bit’s design that renders it almost totally useless when it comes to any kind of training which involves direct reining. Again, using direct reining in a snaffle bit, the horse is taught to move away from pressure. To turn to the right, the pressure is on the left side of the horse’s mouth. To turn to the left, the pressure is on the right. There should be no other pressure being applied by the bit that could cause the horse to become confused.

Unfortunately, confusion is precisely what happens to a horse when the Tom Thumb is used. Because of its shanks, any attempt at direct reining results in pressure on several different areas around the horse’s mouth. For instance, if you are aking the horse to turn to the left, you will be pulling on the left rein, with the idea that the pressure from the bit will be on the right side of the horse’s mouth, thereby turning the horse left. However, because the rein is attached to the bottom of a swiveling shank, pulling on the rein results in the shank turning and tipping into the left side of the horse’s face. When the shank tips, it also shifts the mouthpiece, which, in turn, puts pressure on the right side of the horse’s mouth by pulling the right side of the bit into it. You now have pressure on both sides of the horse’s mouth, as well as a shifting of the mouthpiece inside the mouth.

If this wasn’t bad enough, tipping the shank also results in the tightening up of the curb strap that is under the horse’s chin. Suddenly, the simple act of asking the horse to turn to the left is no longer a simple act. The bit is applying so much pressure in so many places, that the horse has no clue as to what you were asking for in the first place.

He then tries to tell you that he doesn’t understand what you want by twisting his neck and shaking his head. Of course, we look at this as him being belligerent and not wanting to do what he was told. So, we simply apply more pressure to the rein which resluts in an even bigger fight on his part.

Eventually, the horse does finally turn to the left – but only as a last resort. Before he does, he will first try several different options. Among these will be: 1) turning to the right, because the left shank tipping into the side of his face is forcing him that way; 2) lifting his head as high as he can get it; 3) dropping his head as low as he can get it; 4) backing up. Rearing is also an option which sometimes happens as well.

The rider is beginning to pick up the left rein in this photo.

Even though there is still slack in the rein, you can see the left shank of the bit is beginning to put downward pressure on the headstall (which transfers to pressure over the poll of the horse). The left shank is also beginning to pivot on the hinge in the bit, indenting the horses face just below the cheek teeth. The curb strap is already fairly tight on the left side, even with this slight pressure on the rein. The mouthpiece is beginning to create a “V” inside the horse’s mouth as the joint in the center of the bit begins to collapse.

This shows a horse’s typical response to a simple request to back up when using the Tom Thumb bit.

The left shank of the bit has turned into the horse’s face, and the curb strap has tightened. The horse is opening his mouth in confusion, and in an attempt to eliminate the pressure.

Asking the horse to stop or back up, using a Tom Thumb, often results in much the same behavior. The reson for this is, again, the bit’s design. Pulling back on the reins causes the hinged mouthpiece of the bit to collapse and jut foreward and then downward inside the horse’s mouth, putting pressure on the horse’s tongue. At the same time, the bottoms of the shanks (where the reins are attached) tip backward, causing the top of the shanks to tip forward. This, in turn, causes the curb strap to tighten under the horse’s chin. Again, pressure is being applied in several different areas and this results in total confusion for the horse.

Neck reining with the Tom Thumb can also result in confusion on the horse’s part. This is because the idea behind neck reining is to be able to turn the horse by applying light pressure on his neck from the rein. To turn to the right, the rein is laid on the left side of the horse’s neck. To turn to the left, the rein is on the right side of his neck. When done properly, there should be no movement or involvement whatsoever on the part of the bit. The solid curb bit, because of its design, lends itself very well to the act of neck reining. When laying the rein on the horse’s neck to turn him, even if slightly heavy pressure is being applied, the curb bit usually will not move in the horse’s mouth. This helps to eliminate the possibility of mixed signals which could confuse the horse.

However, because the Tom Thumb has so many moving parts, even the lightest pressure during neck reining with it often results in the shifting of the bit. Again, the shanks tip and turn causing the curb strap to tighten, the mouthpiece to collapse and the horse to become confused. The horse usually responds by raising his head and tipping it to the outside, or in the opposite direction that you want him to turn. Our response is usually to grab the reins with both hands and direct rein the horse back in the direction we want him to go. Of course this begins the series of problems that I mentioned earlier, head shaking, head tossing, and almost total unresponsiveness to anything we ask the horse to do.

In just about every case, when I’ve been asked to help someone overcome an unresponsiveness problem in their horse, the problem has usually stemmed from the use of a Tom Thumb snaffle, or some other type of long-shanked snaffle bit. However, that is not always the only cause of the problem. Very often the use of one of these bits is coupled with the person’s inexperience in working with problem horses in general, and is made worse by their inabiliity to recognize that a problem even exists. Many times they dismiss the head tossing, and lack of responsiveness that accompanies the use of one of these bits as the horse being grumpy or belligerent. Therefore, any time the horse begins to “act up” they simply get a little move heavy-handed with him, forcing him to do what is wanted, instead of looking for what has caused the problem to begin with. Usually, this only serves to intensify the problem.

This is a full cheek snaffle bit. The rider is beginning to pick up the left rein.

The bit is swivelling out and away from the horse’s face, while the mouthpiece remains stationary in the horse’s mouth.

This shows the same situation as above, from the right side.

The full cheek bit has slid very slightly through the horse’s mouth (to the left), and the full cheek portion of the bit is beginning to lay along the horse’s face on the right side, giving a clear signal asking the horse to move his head away from the pressure on the right side of his face by moving his head to the left.

It is not meant to imply that the use of one of these bits is the only cause of unresponsive behavior in horses, or that the Tom Thumb is the only type of bit that will cause it. After all, any kind of bit in the hands of a unknowing or uncaring rider can easily be transformed into a weapon. What is true is that this particular style of bit has been the cause of more problem behavior than any other I have seen and is definitely not one I would recommend using – especially for the inexperienced horse person.

If you are currently using a Tom Thumb snaffle or any other type of similar bit and you are happy with the way your horse is responding, then by all means, don’t switch it. If however, you are experiencing some or all of the problems I have mentioned and are currently using – or are thinking about trying – a Tom Thumb, then you may want to reconsider its use.

As with any type of problem behavior concerning horses, it is very important to know and understand what your personal limitations are in dealing with them. Someone with limited training experience should always seek help from an experienced professional. Well-meaning but unknowing friends trying to give free advice often only serve to compound the problem. It is also important to remember that, when it comes to bits, the simpler it is for the rider to use, the simpler it is for the horse to understand. A clear cue on our part makes for a clear response on the horse’s part.


  • Tammy said:

    Thank you so much for a wonderful article. I see so many people who think that the Tom Thumb is a mild bit. I started riding reining horses in 1972 and was fortunate enough to learn the old Spanish progression (snaffle-hackamore-curb). I was told at that time that the Tom Thumb had no place in any valid training program and have never used it. Thank you for explaining exactly why they are a bad idea. I will pass it on.

  • Brandon Price said:

    Awesome write up. I wish more people would do research before blindly sticking a bit on a horse. I was given a Tom Thumb years ago but never used it. This article convinces me that the only use for it is a toilet paper holder.

  • Katie said:

    I use a full cheek snaffle bit in western..it’s what I’ve always used, my friend bought the bit, and he knows alot about horses too. But now I have two people telling me that it is strictly an english bit. How does that work? I barrel race, and do everything in it. I have no problems whatsoever with using it in western. What are your thoughts on this?

Leave your response!

Add your comment below, or trackback from your own site. You can also subscribe to these comments via RSS.

Be nice. Keep it clean. Stay on topic. No spam.

You can use these tags:
<a href="" title=""> <abbr title=""> <acronym title=""> <b> <blockquote cite=""> <cite> <code> <del datetime=""> <em> <i> <q cite=""> <s> <strike> <strong>

This is a Gravatar-enabled weblog. To get your own globally-recognized-avatar, please register at Gravatar.

CommentLuv badge