Step 1: Set cleats.
Slip on your shoes, run masking tape along the instep, and mark it at the widest point of your foot. Align the middle of the cleat with that line, or up to 2 centimeters behind it, says fitter Paraic McGlynn of Faster, a shop in Scottsdale, Arizona.
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Step 2: Assume a natural cycling position.
Warm up for 15 minutes, then extend your right leg as if it were the little hand of a clock pointing to 5:30 (use a trainer or balance against a wall). Most riders' heels rise while pedaling. Lift yours 2 centimeters above the pedal when your leg is extended. (Search: What causes knee pain while cycling?)
Step 3: Measure knee angle.
Raise or lower your saddle. Have a friend measure your knee bend, aiming for 25 to 35 degrees. That's the sweet spot for producing maximum power.
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Step 4: Set fore/aft position.
With cranks level, lower a plumb bob (tie a 30-inch piece of string to a rock if you don't have one) from the front of your kneecap to where the pedal spindle connects to the crank arm. If the line falls in front of or behind the spindle, slide your seat forward or back, then recheck.
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Step 5: Save.
Measure from the center of the bottom bracket to the seat top. Then drop the plumb bob from your saddle tip and measure from the string to the center of the bottom bracket. Record both numbers and mark the correct position on your seatpost and saddle rails.
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