Structural defects can be categorized as either unsoundness or asymmetry. Saddles with either of these defects are likely to cause physical pain for both horse and rider and should not be used.
Saddle SoundnessSoundness problems can be caused by either poor design or poor saddle care. The most common example is a cracked or broken saddle tree. While this is most often seen in older saddles that have been abused, it can also be found in low quality new saddles. You should always test the tree before purchasing any saddle, new or used.
To test, set the saddle on the fork (or pommel), nose down. Press down hard on the cantle and look for bending which is an indication of a broken or cracked tree. A broken or cracked saddle tree is compromised and should not be repaired. It will always be unstable.
Saddle SymmetryEvery saddle should be symmetrical from every angle with everything in the exact same position on each side. Asymmetry is usually caused by poor design, but an uneven rider or horse can cause a saddle to become asymmetrical over time.
An asymmetrical saddle will apply uneven pressure to the horse and can cause physical pain for both horse and rider. The most critical parts are the rigging plates (or billets) and the fenders and stirrup leathers. If their position is not in exactly the same on each side, the saddle will be off balance, causing the saddle to twist and shift to one side. Before purchasing a saddle, check a saddle over carefully for symmetry.
Saddles with structural defects will never be "right" regardless of the shape of the horse.
Beth Stefani is the publisher of the http://www.Western-Saddle-Guide.com. Whether you're just starting out with horses or a seasoned horseman, the Western Saddle Guide provides all the information you need to understand, choose, and care for the saddle that's right for you.