Easy Guide: Replacing Your Bicycle Seat – Step-by-Step

Knowing how to change a bicycle seat is easy. You will need a wrench that fits either 4mm, 5mm, or 6mm Allen bolts, depending on what size bolts your bicycle seat uses. The most challenging part of the process is adjusting the new seat for comfort, proper height, and proper positioning front to back. 

1. Select the wrench that  fits the Allen bolts on your bicycle. The bolts are located under the seat on the seat post clamp.
2. Unscrew the bolt under the seat. Some bicycle seats have one bolt in the center, some have two bolts on either side. A one-bolt seat should be loosened enough so that the top piece can move. This exposes the rails and the seat will come off. With a two-bolt seat, both bolts should be removed completely so you can pull off the top and remove the seat. 
3. Take the new seat and place it so that the two rails are in the slots in the clamp. Tighten just enough to keep it secure.
4. Adjust the seat height by loosening the pinch bolt where the seat post fits into the frame. Tighten the pinch bolt when the seat is at a comfortable height.
5. Adjust the seat angle and position by loosening the seat clamp, then tighten after adjustment is made.
6. Adjust the forward and backward positioning by sliding the seat back and forth in the rails.
7. After the adjustments are made, tighten all the bolts tightly with the Allen wrench.

To make sure that your new bicycle seat is adjusted properly, test it before your tighten the bolts completely. Sit on it and place your foot on the pedal. If you feel uncomfortable, either too cramped or are stretching to reach the pedals, then make additional adjustments.