One saddle. One concept. Endless solutions∞
Discover the Equation Saddle on video
Designed for horse and rider together, adaptable to the way you ride.
The Equation saddle is the modular, adjustable and interchangeable saddle by Sellerie Gaston Mercier. Front and rear panels that move, interchangeable flocking, an adjustable and interchangeable seat, interchangeable flaps, and tree bars that are free and independent on the right and left: every part adapts.
One saddle, fitted to your horse’s back over time, with interchangeable flaps and seat to move from dressage to jumping, from flatwork to hacking.
Your horse keeps its bearings, you keep your seat. It was born in our workshop in Aveyron, France, from hands that cut, stitch and build leather the way it has always been done.
Book an appointment →A patented base, everything else adapts.
Tree size, seat size, panels, flocking and flaps: everything is interchangeable. At the first appointment, our saddle fitter sets the base to your horse’s back; you then build your saddle around the way you ride.




7 configurations, one single saddle.
From dressage to endurance, choose the flaps that suit your riding.








A saddle fitter helps you choose the right flaps for the way you ride.
Book an appointmentYour horse keeps its bearings, you keep your seat.
One saddle, fitted to your horse’s back, from flatwork to jumping.







All about the Equation saddle
What is the Equation saddle?
The Equation saddle is the modular, adjustable and interchangeable saddle by Sellerie Gaston Mercier. A single saddle adapts to your horse’s back, your build and your riding: panels, flocking, seat, flaps and tree bars can be adjusted or swapped. It is handmade in our workshop in Aveyron, France.
What is the difference between adjustable, modular and interchangeable?
Adjustable: the saddle can be set up (seat position, front and rear panel mobility). Modular: it is made of separate components assembled on a base. Interchangeable: each component (flaps, seat, flocking) can be replaced by another, depending on the horse, the rider or the discipline.
Which parts of the saddle can be adjusted or changed?
The panels move at the front and at the back, and their flocking is interchangeable (length, thickness, density). The seat is adjustable and interchangeable. The flaps are interchangeable depending on the discipline. The tree bars give freedom and independence on the right and left sides.
Why independent tree bars on the right and left?
A horse’s back is never perfectly symmetrical. Independent right and left tree bars give the horse’s back more freedom and allow a finer fit, for the horse’s comfort and the rider’s balance.
Can I change the flaps myself?
Yes. The flaps are screwed on and can be changed easily by the rider, without touching the base settings. You can switch from dressage to jumping, from flatwork to hacking.
Which disciplines is the Equation saddle suited to?
Seven flap configurations are currently available: dressage (Doline II, Doline III), jumping and cross-country (D13), general purpose (Muze, Compiègne), trail and endurance (Margeride) and endurance (Florac 2.0).
Will the saddle adapt if my horse changes?
Yes, that is the whole point of the Equation saddle: it adjusts over time. When your horse’s back changes, or if you change horse, the panels, flocking and tree size can be modified without buying a whole new saddle.
How can I try the Equation saddle?
Book a personalised saddle assessment: a saddle fitter comes to you and sets the base to your horse’s back at the first appointment. You can also try it at our test centre, Le Mas de Vinaigre, Saint-Léons (Aveyron, France), by appointment.
Come and try it, or we come to you.
Appointment with a saddle fitter
Our fitter comes to you, assesses your horse and recommends the right configuration. At the first appointment, the base is set to your horse’s back.
Book an appointmentAt Le Mas de Vinaigre, Aveyron, France
In our test centre, inside the workshop, ride the Equation saddle, swap the flaps and feel the difference. By appointment.
393 Route du Mas de Vinaigre, Le Mas de Vinaigre
12780 Saint-Léons, France · +33 5 65 47 60 98
contact@gaston-mercier.com