Choose the right size of bicycle by comparing your height to the handlebar position and the height of the seat and frame. Get someone to hold the bike while you measure it, and make sure the stem fits properly. This process takes 15 minutes.
- Straddle the top tube
Stand over the bike's top tube with your feet flat on the ground. For road bikes with a straight top tube, strive for 1 inch of clearance between you and the tube. For mountain bikes, strive for 2 to 5 inches of clearance. Children need 2 to 4 inches of clearance regardless of the type of top tube.
- Adjust the seat height
Get someone to hold the bike while you sit on the seat. Extend one pedal all the way down. To find your ideal seat height, adjust the seat so your leg is 80 to 90 percent extended and your knee bends slightly.
- Check the stem
To check whether the stem of the bicycle fits properly, grip the handlebars and look in a mirror, or get someone to check the angle of your back. A properly fitting stem puts your back at a 45-degree angle, letting you reach the gears easily and absorb road bumps.