Custom fitting begins and ends with good measurements from your body and your current bike.
Please have another person take all measurements while you are in bare feetor socks and preferably wearing cycling shorts. Please take the measurements very carefully and use millimeters for best accuracy.
Inseam: Using a large carpenter's square, available from any hardware store, stand against a flat wall with feet about pedal-width spread apart in socks or bare feet. Take the square and place it between your legs and pull it upward until it rests against the pelvic arch in the groin. Make sure to hold the back of the square flat against the wall to ensure the top is horizontal to the ground. Take the measurement from the top of the square to the floor in millimeters. Measure twice and take the average.
This measurement will be used to determine your seat tube length and your standover height and your seat height.
Arms: The arm length measurement (figure 1, dimension A) goes from the end of the clavicle to the outer fold of the wrist with the arm outstretched. Measure both arms and take the average. You will most likely find that your arm and torso measurements are within a cm or two. If they are not, double check by remeasuring.
This measurement is combined with your torso measurement to determine your effective top tube length as well as other important cockpit dimensions.
Torso: The torso length measurement (figure 1, dimension B) goes from the top of the inseam measurement to the upper edge of the sternum (the soft, fleshy indentation at the center of the base of the neck)
Shoulders: This is the measurement from one end of the clavicle to the other, across your back.
This measurement will determine your handlebar width.
Height: Measure your overall height while standing erect with your feet about two inches apart.
Weight: Stand on a properly calibrated and accurate scale.
This helps to determine the proper tubing diameter and thickness selection.
Feet: Average the measurements of your feet. Or what size cycling shoe fits you best?
This measurement will help eliminate any toe clip overlap.
Flexibility: Standing on a flat surface with your feet about 4 inches apart, and keeping your legs straight, can you touch the floor? if yes then you are a TEN! Can't make it past your mid section? Then you are a one and so on and so forth.
This measurement value helps to determine the height of your saddle over the height of your handlebars.
Top Tube Length (center to center):
Horizontal top tube frame (some road bikes): Measure from the center of the head tube at the head tube / top tube junction to the center of the seat tube at the seat tube / top tube junction.
Sloping top tube frame (compact road bikes and mountain bikes): Measure from the center of the head tube at the head tube / top tube junction horizontally (parallel to the ground) to the center of the seat post or seat tube.
Seat Tube Length:
Measure the total length from the center of the BB to the top of the seat tube.
Measure from the center of the steerer clamp to the center of the bar clamp, along the stem’s extension. Most stems are only available in 5mm increments and typically range from 80 – 140mm.
Using an angle finder or protractor, measure the angle between the head tube and the stem’s extension. Typical values range from 73 deg to 105 deg. Or look on the stem for specifications that may e printed on it.
Saddle Center To Bar and Saddle Tip to Bar
Measure from the center of the saddle (at center line of seat post) to the center of the stem clamp where it holds the bar. Then measure again from the tip to bar center.
Saddle To Floor
Measure from the top of the center of the saddle (at center line of seat post) to the ground vertically. A plumb line dropped from the center of the saddle helps accuracy.
Bar To Floor
Measure from the top of the bar (next to the stem clamp) to the floor. A plumb line helps with this measurement too.
Head tube length
Measure the length of the head tube from end to end, not including the headset cups.
Measure form the center of the bottom bracket to the center of the front axle.
Measure along the seat tube from the center of the bottom bracket to the top of the saddle.
Drop plumb line from the saddle center measured at the centerline of the seat post and measure from the plumb line horizontally to the center of the bottom bracket.
Measure your seat post from the centerline of the post tube back to the center of the seat camp bolt
Measure from the flat ground to the top of the top tube at its center point between the head and seat tubes.