Part One: Understanding the Cheek Piece
By Tristan Mahoney, TM Bits & Spurs
Before you can choose the right bit for your horse, you need to understand how a bit actually works. Not just what it looks like — but what it does, and why. This series is going to break that down piece by piece, starting with the foundation of every western performance bit: the cheek piece.
The Two Parts of a Cheek Piece
Every cheek piece is made up of two elements — the purchase and the shank.
The purchase is measured from the top of the headstall ring down to the top of the mouthpiece. The shank is measured from the bottom of the mouthpiece down to the bottom of the rein ring.
These two elements work together, and understanding the relationship between them is the key to understanding why one bit feels completely different from another — even when they look nearly identical at a glance.
The 1:2 Ratio — A Proven Starting Point
The most common cheek piece we build here at TM has a 2.5" purchase and a 5" shank. That's a 1:2 purchase-to-shank ratio.
We didn't invent this. Horsemen have been arriving at this ratio for centuries because it works. It's balanced, it's responsive without being abrupt, and it gives most horses and riders a feel that communicates clearly without creating anxiety. It's our baseline — and it's a baseline for good reason.
But it isn't the only answer. It's just the starting point.
What Happens When You Change the Ratio
To understand how changing the purchase or shank affects the feel, think of the mouthpiece as a pivot point. Everything above it and below it is rotating around that center when you pick up the reins.
A shorter purchase speeds everything up. The mouthpiece and curb chain engage more quickly when the reins are lifted, and when the bit is fully engaged the rein ring travels further back — giving the rider more leverage and a quicker, more direct response. This is the right setup for a horse that needs a faster, cleaner signal.
A longer purchase does the opposite. Engagement is slower and more gradual, the rein ring doesn't travel as far back when fully engaged, and the overall feel is softer and more mild. This works well for a horse that's sensitive, still developing, or one that a rider wants to ride with a lighter, more progressive touch.
Same mouthpiece. Same basic design. Completely different conversation with your horse — just by changing the length of the purchase.
Why This Matters
Most riders pick a bit based on what it looks like or what someone else is riding. The best riders pick a bit based on what their horse needs to hear — and then they find the geometry that delivers that message most clearly.
That's what this series is about. Not what's popular. Not what wins on looks. What works for your horse.
