Abstract: A stirrup for a horse riding saddle has a cylindrical bolt attached across its open end which, in a conventional fashion, rests in the bottom loop of a stirrup strap which in turn is attached to the saddle fender to hold the stirrup in place. The bolt comprises a cylindrical sleeve with movable pins or rods having keyed outer ends extending axially out of the sleeve for engaging keyed openings at the open end of the stirrup and a spring within the sleeve applies a force to the pins to disengage them from the keyed openings while a greater and opposite force is applied by radially extending finger means to hold the pins in place. If the stirrup swings in an arc with respect to the stirrup strap which exceeds a predetermined angle the force applied by the finger is disengaged from the pins so that the force of the spring takes over and disengages the pins from the keyed openings in the stirrup to allow the stirrup to fall free.