April 25, 2012
Five Steps to Perfect Seat Adjustment
- Level the seat and center the rails in the seatpost clamp.
- Wearing cycling clothing, put the bike in a trainer or position yourself in a doorway so you can hold yourself up while pedaling. Have a friend sit behind you and watch as you pedal backwards. Raise the seat until when you pedal backwards with your heels on the pedals, your legs are completely extended at the bottom of the stroke. If you have to rock your hips to reach the pedals the seat is too high.
- Mark the seatpost so you’ll be able to refind this starting seat height if the post slips or you take it out to ship the bike, etc.
- Find the proper fore/aft seat position by placing the bike on a trainer (the bike must be level with the ground) and pedaling a while to warm up the muscles. Stop pedaling with one foot at 3 o’clock. Have your assistant level the crankarm and the pedal. Maintain that position while your helper holds a plumb line (a thread with a nut on the end works fine) against the indentation just beneath the bone that’s below your kneecap. Adjust the seat fore and aft on the rails until the plumb line bisects the pedal axle.
- If the nose of the seat bothers you, tip the seat down 1 to 3 degrees. Don’t overdo it because a tipped seat will cause your body to shift forward putting added pressure on the knees and preventing the seat from supporting your weight adequately. If the nose bothers you enough that you want to tip is excessively, try different seat designs.