|The seat in a western saddle is measured in inches such as 14", 15".15 1/2", 16".etc. The measurement is taken on the bare tree before the saddle is built (see figure 1).
The western saddle tree seat size should be measured from the back of the swell at the top of the gullet (point X) back to leading edge of the cantle or cantle board (point Y). Again, as stated before, tree makers have developed their own measurements and methods and may use other reference points. These measurements are for the rider. The top of the gullet at the back of the swell is chosen for uniformity.
In figure 2 (point X) the top of the gullet at the back of the swell and (point Y) the leading edge of the cantle is the same for the Cliff Wade tree and the Buster Welch are the same.
Another widely used reference point is the base of the horn at the back of the swell (see point B in figure 2). This reference point presents a problem in that swells will have a forward "tilt" to them in other words the swell is not vertical but leans forward. This forward "tilt" varies depending upon the swell type. In figure 2 the Buster Welch Cutter tree has a swell that has little "tilt" as indicated by the distance between (point B) and (point X). While the Cliff Wade tree has more "tilt" as seen by the distance between (point B) and (point X). When this reference point is used the seat size could be larger than the actual seat size and lead to confusion.
See below for an example:
In the example the measurement taken on a bare tree from the base of the horn is just under 3/8 of inch longer than the measurement taken on a bare tree from the top of the gullet which is 15". On the sample Cliff Wade tree the difference is 1/2".