How Breakaway Stirrups Work

S.T.I.’s safety breakaway stirrup is designed to “breakaway” from the saddle when the rider is in danger of getting “hung up” in their stirrup, and being dragged by their horse. As a rider falls to the ground, their bottom drops below their heel and their toe will come up, this will rotate the stirrup around the stirrup leather, releasing the mechanism. The release mechanism is a precision-engineered safety device, designed to release itself from the stirrup leather when it reaches a 72° backward angle, or a 45° forward angle. The forward angle can be activated if a rider falls off the horse or gets thrown and hangs their foot up in the stirrup. The backward angle is generally activated when a horse falls and a rider’s foot goes through the stirrup. Whether your foot is all the way through or if your toe is wedged in the stirrup, the stirrup will break away. You can get thrown over the horses head, straight in the air, off the back or out to the side; whether it’s the near side stirrup or the far side stirrup, the stirrup will always rotate before you hit the end of your stirrup leather. These angles of release were scientifically predetermined to be reached only in a dragging situation. In a normal riding situation, a rider’s stirrup won’t generally rotate more than 5°. But even if you're spurring a horse from their shoulder to their hip, with your toes out and down, your stirrups won’t rotate much more than 35°. For the mechanism to release, the rider has to be in a dragging position, or in the process of falling off.   

Rides like a normal stirrup	Disconnects at 45° forward or 72° backward	Rider is freed from horse

  Since the release mechanism functions by angles, it will not be affected by the weight of the rider or the combined forces of a rider’s weight with the horse’s force in a sharp cut, or a quick stop.  This stirrup functions the same for an 80 lb. child, as it does for a 300 lb. adult.  The release mechanism can be most closely related to that of the ski binding.  In field tests it took about 5,000 lbs. of downward force to break out the stainless steel stirrup clip, to release the mechanism.  The steel parts used in the mechanism are investment cast stainless steel parts, that have to maintain .01" tolerances.  The precision of this mechanism gives it the surefire abilities common to a pistol, and the strength to withstand the harshest riding conditions.  The nylon stirrup is made of a reinforced polyurethane nylon, that has also been strength tested in and out of the field.  Horses have fallen on it, laid on it, and we’ve driven tractors over it, without collapsing the stirrup.  If a horse falls on you with your foot in the stirrup, this stirrup won’t collapse around your foot, and wedge your foot into your stirrup, as happens with most conventional western stirrups

The release mechanism is spring loaded, and it takes 8 lbs. of torsion pressure to move those springs, and rotate that stirrup about the stirrup leather.  This was an unexpected benefit, that is truly advantageous to any rider.  The torsion pressure will prevent a lot of the free-swinging motion of conventional stirrups.  Most fall offs are started when someone “blows a stirrup”, that is, the rider’s foot comes out of the stirrup, and puts the rider out of balance.  Picture a child riding at a trot, bouncing 8" out of the saddle.  As his weight comes off the stirrup, most stirrups will swing forward causing a blown stirrup, or swing backwards and the rider’s foot can slip right through that stirrup.  Our stirrup will prevent this motion and about 70% of stirrup blow outs. 

R.L. Tolbert, professional stuntman