how to find your measurements
There are four basic body measurements that establish what frame size and geometry will work best for you. They are: inseam length, sternal notch height, and the lengths of your arms and feet.
To find these four measurements you'll need:
a measuring tape (or a piece of string and a ruler)
a hardcover book
a pen (or pencil, or anything straight you can grip in your fist)
an assistant (if possible!)
Take your shoes off and stand with your back few inches from a wall. Put a hardcover book between your legs, spine up. Bring the spine of the book up to your groin until it rests firmly, but gently, against the soft tissue between your legs. Make sure the short side of the book is square against the wall so that the spine of the book is parallel to the ground.
Have your assistant measure from the top of the book spine straight to the floor. Or, with a pencil, mark the wall where the spine of the book lands, step away, and measure from the mark to the floor.
Note: inseam measurements for bike sizing are different than for tailoring. Please do not use your pant inseam length for this measurement.
Hold a pen or pencil in your fist, and stand straight with your arm hanging at your side, pen parallel to feet. Lift your arm to 45 degrees, keeping it straight. Try to maintain a neutral shoulder (rather than hunching into or reaching away from your joint) and avoid twisting your wrist. With your arm at 45 degrees, the inside of your elbow should be facing forward and your palm facing down.
Measure from the pen in your hand to the side of your body at the ribs, following the line of the arm.
Repeat for the other arm. Measurements will typically be within 0 - 2cm of each other.
Sternal notch height
Keep your shoes off. Standing straight, locate the U-shaped dip at the top of your sternum, between your collar bones. Rest a pen, pencil, or other straight object there. Make sure it is parallel to the ground, not angled up or down. Measure from the bottom of the object straight down to the floor.
By subtracting your inseam measurement from your sternal notch height, we can calculate your torso length.
In either socks of bare feet, stand with your heels against a wall, feet hip-width apart and facing forward. Find the longest part of your foot and mark that spot on the ground. Step away and measure from the mark to the wall.
Repeat for the other foot.