How to Choose the Right Size Bike

In order to decipher a bike sizing chart (the ones that talk about top-tube length and stand-over height), you'll need to know a couple of your measurements. Grab a tape measure, large hardback book (like a coffee table book), a pen and pad, and a friend.

Stand against a wall with your feet shoulder-width apart. Make sure you wear shoes during this procedure (wearing your cycling shoes is best).

Place the spine of the book against your crotch (as far up as it will go) and the bottom edge of the book against the door. Have your friend measure from the top edge of the book straight down to the floor. This is your "inseam" length. Write it down.

Keeping the book in place, have your friend measure from the same top edge of the book up to the "V" in your neck (right above your sternum).

NOTE: make sure the tape measure is straight up and not angled back from the book edge to your neck.

This is your torso length. Write it down.

You can now remove the book. It's time to measure your arm length. Stretch one arm out to your side, holding it parallel to the floor, and make a fist. Turn your fist so your thumb is the closest part of your hand to the ceiling.

Have your friend measure from the end of your collarbone to the center of your closed fist. This is your arm length. Write it down.

Now we need to put all these measurements to good use.

When a bike sizing chart talks about stand-over height, you'll need your inseam length to determine your clearance. Follow this guideline for different bikes:

-Road bikes need 1" to 2" of clearance.
-Mountain and Commuting bikes need 2" to 4" of clearance.

Clearance equals your inseam minus the bike's listed stand-over height.

The other important measurement on a sizing chart is top-tube length. To calculate the correct top-tube length for your fit, add your torso length and arm length together, divide that number in half and take away 6. The result is how long your top-tube length should be, measured in inches.

If you follow these guidelines, and properly measure yourself, you'll be able to find the right size bike the first time!

NOTE: some bike companies are using centimeters instead of inches:
1 cm = 0.39 inches. You can do the math!