The x-seam measurement is used to estimate whether or not a person will fit on a recumbent bicycle. It is especially useful for very tall/large people and very small people who may fall outside the fit range of a recumbent bicycle.
Here is the simplest way to measure x-seam. You don't even need to get on the floor.
- Stand inside a door frame (no shoes) with knees straight, heels flat on the floor and against one side of the door frame.
- Bend forward at the waist and rest your head on the other side of the door frame.
- Reach behind your back with either hand and slide the back of your hand down your back until the fat part of your hand stops on the door frame.
- Keep your hand exactly where it stopped or place a Post-it note to mark the spot and measure from the floor to the bottom edge of your hand.