We use a sizing measurement called an X-Seam. This measurement helps us to determine which size will best fit you. Here is how we you determine your X-Seam size.
Wear shoes you would typically use for riding. Sit very tight against the bottom of the board, lean back, and stretch your legs out straight with the soles of your shoes perpendicular to the floor. Measure the distance in inches from the front of board to the bottom of your shoe. This is an important measurement so have an assistant help you get an accurate number. Use an ironing board, a piece of plywood or whatever you can find. Lean it against a wall at the recommended angle or as close to it as you can eyeball.
The boom tube length guidelines listed below are merely suggestions, this is by no means an exact science. For those of you who are on the fence, here are some guidelines. If you're the serious racing type who likes to recline the seat all the way back and go fast, add an inch to your x-seam measurement. If you're more inclined (no pun) to sit very upright and just cruise around town and be cool, you might need to subtract an inch.