To figure out what length you need your stirrup leathers at simply measure from the stirrup bar you intend to use (front or back), down to the stirrup set at the length you wish to have and folded back up until the end is just below the flap. You do not want the T bar fixing on the flap. We recommend using a bit of baler twine to help get your length correct. However, please do not ride using the twine!