There is very little standardization in the way saddles fit - particularly when it comes to width. Tree construction varies from company to company, so one company's medium may be comparable to another company's medium-wide or wide. Trees made in the UK to BETA (British Equestrian Trade Ass'n.) standards have to be within a certain angle measurement - a medium, for example, between 85° and 94.9°, and a wide between 95° and 104.9° - but that's almost 10° variation. Even centimeter measurements, which you'd think would be a more exacting way of measuring width, aren't much help. A 29 cm. Passier (that company's x-wide tree) will fit a wider horse than a 32 cm. Stubben.
Why? Tree point length. Saddles measured in centimeters are measured between the tree points on the bare tree, before the saddle is built. So if you have an 8" long point, 32 cm. will be considerably less generous than if the points are 5" long. To illustrate, I've compared a 28.5 cm. "wide" Passier with an "xw" Stubben (which, according to Stubben's web site, is wider than a 32 cm., though no exact width measurement is listed).
Measured from the saddle nail down to the end of the point, it's just about 5":
Now, here's the Stubben, with Edie's index finger again at the end of the tree point:
And here's the length of the point - about 8":
Here's a comparison of the same saddles (remember, Stubben xw, Passier wide, 28.5 cm.) from the front, with the ends of the tree points marked with tape. First, the Passier:
Though it's hard to see, the measurement is just under 12".
Here's the Stubben:
Again, hard to see the numbers, but it's measuring about 12 1/2".
The longer points on the Stubben can be helpful when fitting a horse with a good wither - they distribute the weight all the way down the wither. But on a horse with moderate to no wither, long points can make the saddle "perch" and cause lateral instability.
And when you add panel configuration and tree shape into the mix, it can be even more confusing. A K panel or a wither (or full front) gusset will make a saddle fit less generously. A hoop / freedom head tree or a panel that's attached lower down in the gullet (like Passier's Freedom panel) will make a saddle more generous in the width department. Here's a photo with three saddles - all 34 cm. trees - so you can see the variation in width. The top saddle is a Duett Largo, built on a hoop-type tree; the middle is a Prestige 2000D, and the bottom saddle is a Duett Fidelio.
And to get an idea of how panel configuration figures in, here are two Black Country saddles - an Eloquence X on top, and a Vinici X on bottom. Both are 17.5" wides, built on the same tree ... but look at the difference.
So if you're in the market for a saddle, remember that describing your horse as needing a "wide" tree or a "33 cm. tree" can be open to a LOT of interpretation.
