These irons have a bent leg to prevent the foot from being caught in the stirrup in the event of a fall.
The correct way to measure stirrup irons is between the two “uprights” ie the width of the metal tread. There should be 1/2″ clearance on each side of your riding boots.
Stirrup Irons are measured by the inside opening of the stirrup where the foot is placed Do not measure along the underneath of the iron.