Your stirrups should be one inch (2.5cm) wider than the width of your boot at the ball of the foot. When your foot is in place, you should have ½ inch of space on each side. While you don't want your boot to fit too snugly into your iron, you also don't want your stirrup to be too wide.
Size | Stirrup Width |
---|---|
110 | 4.33" |
120 | 4.72" |
125 | 4.92" |
130 | 5.11" |