The saddle as a feedback loop

In another lifetime I learned to use a form of systems theory to analyze and improve my organization’s business processes. We were a state agency that issued professional licenses and resolved consumer complaints. One basic analytic tool we used was the simple feedback loop.

For example, we flow-charted our administrative and legal processes into a series of discrete and often interacting steps. We then analyzed these charts to eliminate logjams and improve the system’s effectiveness. This analysis would include highlighting and testing various inputs to the processes that could either improve or impede their ability to achieve their goals.

I remembered all this a while ago when I was working with a client whose saddle always shifted to the right as many saddles tend to do. My client blamed herself –being stronger on the right, she said she tended to step more into the right stirrup, thus pulling the saddle to the right. Maybe so, but solving this seemingly simple problem was really much more complex than it appeared.

Let’s look at this general problem by defining the saddle in motion on a horse’s back as a systems loop. Our goal is to keep the saddle system in equilibrium, basically centered and balanced on the horse’s back. If the saddle falls out of equilibrium – say, falls a bit to the right – we can pinpoint one or more inputs that create a feedback to the saddle position. Some of these inputs may cause a positive feedback – they tend to reinforce the saddle’s movement to the right. Or they may be negative – they may tend to bring the saddle back to center or to the left. Or they may be neutral and have no effect.

For example, the saddle may fall to the right because the saddle tree is twisted or the panels are flocked unevenly. Or, maybe the horse is asymmetrical: larger left shoulder, steeper behind the right, dropped left heel and more upright right foot. Maybe the rider is asymmetrical or stronger on one side. Does the horse want to carry the rider’s weight on his right fore or does he have a lazy left hind? Does he tend to pop his right shoulder, drop his right rib cage and have haunches-in when tracking left? Is he stiff to one side, or are his joints out of whack? Has the horse lost or gained weight or the saddle just does not fit properly?  Any one, or a combination of these inputs, can create feedback to the motion of the saddle. Isolating the root cause therefore is critical to solving the problem.

So the next time you place the blame entirely on yourself for a saddle that leans to one side, consider that you may be missing other inputs to the saddle system that may have a bigger impact than you do as the rider.

You and your saddle fitter both need to consider how each of these inputs can affect the saddle’s behavior. The solution the saddle fitter recommends may be simple or complex, involving more than one input, and usually requires a team approach to achieve. That is, the farrier, veterinarian, chiropractor, body worker, trainer, saddle fitter, saddler, and the rider may all have a role to play in getting that saddle to sit straight.

If you go through the inputs noted above one-by-one, you stand a better chance of isolating all of the feedbacks that may be affecting the saddle and you stand a better chance—systemically—of solving the problem.

Bill Wood

The Saddle Fitter, Inc.

Virginia, USA

Four critical fit points at the front of the saddle

Have you ever heard another rider ask, “I think my saddle is too tight. Do I need a wider tree?”

The answer may surprise you. Often, the saddle that seems too tight is really too wide, and the saddle that seems too wide is too tight. This sounds contradictory if we think of tree width as the only criterion when fitting the front of the saddle. But the head or front of the saddle – the part from the back of the stirrup bars through the front of the pommel – actually has four critical fit points or angles that must match your horse for the saddle to fit correctly.

The four critical fit areas are:

1)     Head shape (pommel arch)

2)     Tree width

3)     Gullet width

4)     Mouth

In this entry I explain the basics of these four critical fit areas to show how they come together to create a good – or bad – fit.

Synopsis (for those who don’t want to read a lot of stuff)

1) Saddle fitting seems complex, but boils down to matching the different angles of the saddle to the same angles on the horse. This is especially true at the head of the saddle – although we have to understand that the tree width, or angle of, or distance between, the tree points, is just one consideration.

2) If the gullet channel at the stirrup bars is too narrow, the saddle looks too wide, even if the mouth and arch are moderately sized and the tree “width” is correct. This kind of tree perches on the stirrup bar area of the panels and creates pressure points along the withers. (A pressure point is an area of high pressure repeated over time that causes the pain, spasm, tissue-breakdown cycle.)

3) If the gullet channel is appropriately sized for the horse, but the mouth of the saddle is too open, the panels through the stirrup bar area will again cause pressure points. An overly open mouth does not “free the shoulders.” Instead, it creates pressure points at the stirrup bars. These high pressure areas pinch at least four of the seven muscles responsible for holding the shoulder to the horse and helping the protraction and retraction of the front legs.

4)  If the tops of panels at the pommel drop into the back of the horse’s shoulders, the saddle may be too wide, not too tight as some think.

Head Shape (Pommel Arch)

Just like people have different heads shapes, from pointy to pumpkin headed, the front arch of the saddle head comes in a variety of shapes. It is critical to match the right head shape to each horse.A tree maker can use an infinite number of head shapes, but all will tend toward one of these three basic shapes.

  1. An A-frame, such as a saddle we would use on a high-withered horse like a thoroughbred
  2. An upside-down U shape, for a “nicely built” warm blood
  3. A hoop or half-barrel for broad, flatter-withered horses. (Anything from a Morgan to a draft or a big warm blood.)

It is important to match the head of a saddle to the shape of the horse, regardless of tree size. For example, a tall, rangy Ukrainian warm blood with high withers may tend toward a broader A-frame shape, and a saddle with a generous U-shape head will sit too close to the withers. It will not shape well to the muscles behind the shoulders because the broad head does not match the horse’s slimmer angles. On the other hand, a muscular working quarter horse may tend toward a small hoop shape, where even a wide tree standard U-head could perch too high on him.

Tree Width

Trees come in different sizes, such as narrow, medium, wide, and the many sizes in between, such as medium narrow and medium wide. Saddles can even come in really wide sizes, such as extra wide, 2X or even wider. Typically, the angle of the tree points – the structural, weight-bearing parts of the tree that wrap from side-to-side around the top and bottom of the pommel –determines the tree size. Many tree widths are then measured by the distance between the bottoms of the steel plates that are riveted to the underside of the tree points to give them strength. This measurement is usually taken in centimeters and then can be translated by the saddle maker as narrow, medium or wide, etc. as a common reverence for the retail market. Some saddlers will also use width references such as centimeters (29, 31, 33, etc.) or single numbers such as 3, 4, or 5.

Since the saddle industry makes a variety of tree shapes and sizes, similar tree widths may fit differentlyfrom brand-to-brand or model-to-model. So don’t assume, for example, that the medium wide tree in the new saddle will fit the same as the medium wide tree in your old saddle. If you are not sure, have a professional fit it for you.

But the correct tree size or width is just the start of finding the right saddle to fit your horse.

Gullet Channel Width

The gullet channel is the space between the two panels (which sit directly against the horse), running the length of the saddle. In general, the gullet should be wide enough to clear the sides of the horse’s spine by about a half an inch on each side.

If the gullet channel at the back of the head is too narrow, the front of the saddle will perch on and pinch the muscles around the withers behind the shoulders. This occurs regardless of a more open mouth and wider tree size.

A gullet that is too wide will dwarf a horse that has higher, narrower withers—the whole front of the saddle will be unstable.


Some saddle gullet channels have parallel panels, where the right and left panels maintain a roughly even distance between them from front to back, or an angled channel, where the gullet channel becomes continuously wider from the back of the saddle to the front.

Parallel panels have a closed mouth; an open mouth occurs when the gullet channel at the mouth of the saddle is wider than the gullet channel at the back of the stirrup bars.

I measure the saddle’s mouth using my fist. (I know the measure “my fist” is inexact, but start measuring saddle heads this way and develop your own definition.) The gullet channel at the back of the head (the stirrup bar area) will typically range from a very tight fist to a very roomy fist that has a half an inch or more width in addition to your fist. I consider a headto be very open or ‘frogmouth’ if the gullet width is two inches or more in width from the back of the head to the front of the head. A saddle is closed-mouth when the difference is one inch or less. A closed mouth saddle usually has parallel panels, while a frogmouth saddle has angled gullet channels.

Closed mouth saddles will generally sit tight to the back of the scapula on horses that are very uphill to the shoulders, while frogmouth saddles will be too open for horses where the angle of the muscles from the back to the front where the saddle sits is lest acute.

A frogmouth represents the most common saddle-fitting problem. In an attempt to “free the horse’s shoulders,” some in the saddle industry mistakenly create a frogmouth. This causes  the front of the tree (the entire length of the tree points) to flare away from the back of the shoulders, leaving a space along the tree points such that the saddle bears little or no weight along their length, ostensibly leaving the shoulders free to move backward on protraction. This is a mistake because the tree is designed (in theory) to bear weight equally from front to back. If the tree points make little or no contact, the horse has to bear the weight at the front of the saddle elsewhere, typically at the stirrup bars. All of the rider’s weight and pull of the girth at the front of the saddle, therefore, falls on the very small stirrup bar area of the panels. This typically creates pressure points on the horse under the stirrup bars. A pressure point is a tack-related area of high pressure on a horse that is repeated over time. Pressure points cause a pain-spasm-tissue breakdown cycle. This is especially true for spring tree saddles, where the tree has some flex to it. I have stood on the middle of a bare spring tree, before the seat and panels were attached, and when I did so the stirrup bars flexed inward. This flexing may cause the stirrup bars to create tissue-rending pressure points on the horse. I find stirrup bar area pressure points most damaging to fox hunting horses, since their riders may spend long periods standing in the stirrups.

Stirrup bar pressure points, where created by a spring tree or a too-open mouth, cause the horse to lift his head and hollow his back. If we ask the horse to use his back properly, he has to fight against these pressure points, making them worse. Even if we see no overt tissue damage to the hair and skin there is still muscle pain and breakdown more deeply in the tissue. This will lead to suboptimum performance, even in a talented horse.

The double fulcrum, or, “Don’t see-saws belong on the playground?

I still remember the scene, my buddy and I at age 8 performing a silly stunt on the playground see-saw. My buddy sat on his end of the see-saw resting on the ground. I stretched up to grab the other end and pulled down hard enough to lift him in the air with a bounce. He clung on the handle for dear life. Then “whoosh!” I let go, and he plummeted pell–mell to the ground with a big thud. Heady stuff for two little kids.

Of course, now I know that in mechanical terms a see-saw is a type of Class 1 lever. The lever arm of the see-saw sits on a pivot point, or fulcrum. The load (my buddy) is the object to be lifted at one end of the arm. When force is applied (me) to the other end, the load moves upward without too much effort, the weight of the load being born by the fulcrum.

What’s this got to do with saddle fitting?

I’ve learned that saddle panel pressure on a horse should be even, with few exceptions. Uneven pressure can cause a pain-spasm-tissue breakdown cycle. These pressure points result from repeated high stress over time, according to veterinarian and saddle fit expert Joyce Harman.

Over the nine years I have been fitting saddles, I’ve noticed one problem causes pressure points most often. I call it the “double fulcrum.” (More about other common saddle pressure points in an upcoming “Diary” entry.) That is, the saddle behaves like one, or even two Class 1 levers. These levers can occur separately or together, but in either case the saddle see-saws on the horse’s back, causing pain and tissue breakdown. Sometimes the rider doesn’t even know it is happening.

If the saddle cantle panel curves away from the horse such that a gap occurs between the panel and the horse’s back, and the gap extends under the rider’s seat, then the main point of contact under the back half of the saddle is the fulcrum—the deepest part of the tree. Every time the rider posts and sits in a rising trot, for example, the downward momentum of the rider’s seat forces such a gap to close, much like our see-saw where the kid in the air plummets downward until the back of the see-saw hits the ground.

Whereas the fulcrum of a playground see-saw rests on a firm footing, the saddle fulcrum, the deepest part of the tree, sits on the soft muscle tissue of the horse. Every time the rider sits, the gap under the cantle closes, but only when the deep part of the tree is driven into the soft tissue of the back, creating a pressure point. When the rider rises, her upward momentum on the stirrup bars, combined with the pull of the girth, causes the cantle to rise in the air, only to come down with a crash again as the rider sits. This repeated action causes pressure points on the horse’s back at the deep part of the tree so consistently that I can detect the improper saddle fit just by palpating the horse’s back.

I also frequently find a fulcrum under the area of the panels just beneath the stirrup bars. This fulcrum can typically be caused by an over-stuffed panel (too much flocking), a too-narrow gullet channel between the stirrup bars, or by a too-open mouth at the front of the saddle. In any case, the tautness of girth plus the rider’s weight concentrates pressure under at the stirrup bars. The saddle pivots, and the stirrup bar fulcrum gets driven into the soft tissue, creating pressure points. This fulcrum often coexists with the fulcrum under the deep part of the tree, creating a double fulcrum and two sets of pressure points front and back.

Saddles with these types of fulcrums can rarely be fixed by a flocking adjustment. While adjusting the panel flocking allows the fitter to fine tune and sometimes correct the fit of a saddle, flocking adjustments can rarely solve what is essentially an inappropriately shaped tree for that particular horse.

If your saddle has one or more fulcrums, it may be time to ask your saddle fitter to check the fit, and maybe start thinking about a new saddle.


Bill Wood

The Saddle Fitter, Inc.

Virginia, USA


Why The Saddle Fitter’s Diary

I hope you find my “Diary” entries to be informative and thoughtful. I’ve been fitting saddles for horses and riders for about nine years, and during this time I’ve fitted over 5,000 saddles on almost that many horses. It has been a humbling experience. But along the way I’ve gathered some insights that may help riders, trainers, veterinarians, equine body workers and other saddle fitters deal with the challenges of proper saddle fit.

In sharing my insights, as well as those of the equine professionals that I interview, I hope to give you a deeper understanding of the interaction between rider, saddle and horse that will make your horse happier, your riding more successful, or your clients more understanding.

Saddle fitting has long been an art, and I am thankful to Gary Severson, aka “The Saddle Doctor,” for teaching me the skill of saddle fitting. Then along came Dr. Joyce Harman, a veterinarian who has conducted original research on saddle fitting, and to her I am thankful to have learned that saddle fitting is also a science. The road to knowledge is filled with starts and stops; a properly fitting saddle starts with sound, demonstrable fitting techniques and continues with intuition and insight that can only come from experience and trial.

Put multiple trainers or veterinarians in a room, present them with a problem, and you are likely to get as many solutions as there are people present. Hence, I hope this Diary serves as a spur to thought and discussion to increase our understanding and knowledge of proper saddle fit. I wish it were easy. When we first met, Dr. Harman told me, “I’ve fitted a saddle that I thought was great, and the horse hated it. I’ve also fitted a saddle that I didn’t like, and the horse loved it.” Thus, this Diary is intended to explore the challenges and successes of saddle fitting. While I will often assert, I will just as often ask. If you have a difference of opinion, or don’t understand the point I am making, I hope you will write and tell me so. If you agree, but have something to add, I want to hear from you as well. I will do my best to provide our readers with a representative sampling of your responses.

Finally, I want to add my thanks to the wonderful folks and experts at the Society of Master Saddlers (UK). I’ve enjoyed my relationship with various members of the Society and, as a cheeky American, I am delighted to see that the Society, in spite of its “hidebound” traditions extending back hundreds of years, is still interested in learning and sharing its knowledge with the rest of the world.

Bill Wood

The Saddle Fitter, Inc.

Virginia, USA