Measuring the rider for a side saddle tree
With a regular astride saddle, so long as there is enough room between cantle and fork for the size of the rider, most people seem to get along with them OK (though having a good ground seat built by a good custom saddle maker for them personally makes a world of difference). But a side saddle is a lot more finicky. There are a number of measurements that can be taken to get the top side of the saddle correct for a custom fit for the rider, and here's how they can best be taken.
Taking these measurements isn't difficult. In fact, you will probably spend more time reading this page than actually taking the measurements. However, having someone else to help you is preferable as it is difficult to hold all the tape measures and straight edges by yourself. You will need a tape measure, at least one thing you can use as a straight edge (rulers work well), and either a square or two rulers. And you're ready to go!
Technically you aren't really measuring leg length, but that is what we have decided to call it for now since we couldn't come up with a better name for "back of the butt to behind the right knee" length. The person being measured should sit on a table or counter or something long enough to support the whole distance being measured yet allow her right knee to come up tightly to the edge. It is best to hold the right leg back as much as possible, mimicking the way her legs will be in the side saddle. Then the assistant should put a straight edge vertically down from behind the rider to the table and hold it there while the rider gets down. Measure from the end of the table to the straight edge and you have the leg length. Make sure you hold the measuring tape taut when you take the measurement.
The leg length is used (via a formula) to determine the length from the front of the fixed head to the back of the cantle on the saddle tree, which is called the seat length in North America. (Side saddle seat length is measured differently in the UK than in North America.) This measurement in the finished saddle will be longer than it is in the tree due to padding on the fixed head.
The width of the rider's hips are measured to determine the cantle width needed. The rider must again be seated. They should hold the tape measure with one thumb at the zero point held next to their hip, as shown. Then with the tape measure held taut beneath them, they should grab it with their thumb at the same place on their hip on the other side.
When flattened out, the measurement works out to be right for the cantle width needed.
Where the rider's leg is positioned as it goes over the front of the saddle is very important to how evenly she can sit, and the position, height and shape of the fixed head is also crucial to the rider's position and comfort. Two measurements are needed to get these correct.
With the rider sitting with their leg on a hard, flat surface (a table or a long chair works well) clench your leg muscles tightly. Then place one leg of the square across the top of the right thigh. You should measure at the point on the leg which will be against the fixed head, just a bit back of the inside of the knee. (Measure the left thigh for an offside side saddle.) With the square held against the leg and making sure the legs of the square are truly horizontal and vertical, take the measurement from the top of the leg to the table.
You may, alternately, use two rulers for this. Put one on the table, held vertically next to the leg, and the other one horizontally across the top of the thigh. Take the vertical measurement when they intersect. However, you have to be careful to ensure the rulers really are horizontal and vertical, and not slanted in any way.
This measurement helps us determine the height of the fixed head that will best fit this rider.
With the rider again sitting with their leg on a hard, flat surface with their leg muscles clenched tightly, hold a tape measure or ruler under their leg just back of the inside of the knee where the fixed head will be. With the zero point on the tape measure held at one side of the leg, they should put their thumb close to their leg on the other side without any pressure against their leg and read the measurement beside their thumb. Again, make sure the tape measure is held taut when you read the measurement.
This measurement helps us determine where the fixed head is placed relative to the center of the saddle, as well as the distance needed across the front of the saddle for the rider's leg. Usually the thigh width and height are the very close to the same.
There is always some variation in how people like their saddles to feel, but with these measurements, we can build a tree that will work for the basic size of the rider. Then the saddle maker can custom fit the seat in the saddle to the rider.
(Thanks go out to Lee McLean and her daughter Cait for the pictures and proof reading for this page.)