Riding distances on your road bike provides an excellent workout and helps you build endurance, but it's hard to finish the ride if the bike becomes too uncomfortable. Setting your seat at the proper height helps ensure a comfortable ride and allows you to get the most out of the exercise.
Why Height Is Key
The seat height determines how far you must push down on the pedal to reach the bottom of the stroke, which affects how hard your leg works as well as the angle. If the angle isn't right, you could end up with knee pain during or after your ride. A proper seat height also means you're working more efficiently, allowing you to bike farther than you would be able to if you were wasting energy by pushing the pedals incorrectly.
Basic Adjustment Method
Start by ensuring your bicycle frame is the right height. Straddle the bar in front of the seat with your feet on the floor, and then lift the bike until the bar touches your body -- the tires should be about an inch off the floor. If the bar is slightly slanted, allow 2 inches. Then climb on the bicycle seat, either with a friend supporting the bike or in a doorway so you can use your hands to keep from tipping over, and assume a pedaling position where one foot is at the bottom of the pedal stroke. Even at the bottom, your knee should be slightly bent rather than fully extended -- about 80 to 90 percent straight. Adjust the seat up or down to find the most comfortable angle for your extended leg.
Getting a Little More Technical
Using a simple formula helps you figure out where to set your bike seat. Even with this formula, however, adjust the seat slightly up or down if you experience any discomfort as you ride. Have a friend measure your leg inseam, which is the measurement from the crotch seam in your pants to the floor along the inside of your leg. Multiply that number by 1.09 and set the seat height to the new number. Measure the seat height from the bottom of a pedal when it's fully extended at the bottom of the stroke.
You're Not Alone
Although the basic and 109-percent method are simple to do at home, you might need some professional assistance to set your seat height. A professional bike fitter measures the length of different bones in your legs -- not everyone that's the same height has the same femur length, for example -- and the angles of areas such as your knees and shins. He can also help you determine whether you need to scoot the seat slightly forward or backward to help you find the correct angles. In general, when your foot is halfway down the pedal cycle so the pedal is parallel to the floor, the front edge of your knee should line up with the ball of your foot.