Seized-Part Job · Bicycle

How to Remove a Stuck Bike Seatpost

It slid in easily years ago. It has since become emotionally attached.

Seatposts seize from corrosion between the post and the seat tube, which is worst when an aluminum post sits in a steel frame. It takes days of penetrant and steady, controlled twisting.

The Method

Step by Step

1
Mark the height and loosen the clamp
Mark the post’s insertion depth with tape. Remove the seatpost clamp completely so it is not adding grip.
2
Soak from the top
Run penetrant around the top of the seat tube and let gravity pull it down.
3
Soak from the bottom
Flip the bike upside down. If the bottom bracket is out, or there is a bottle-cage hole or drain hole, spray up into the seat tube.
4
Wait, then twist
Reapply daily for several days. Then twist the saddle back and forth while pulling up. Steady force, not jerks.
5
Clean and grease on reinstall
Clean the seat tube. Grease a metal post in a metal frame; use carbon assembly paste for any carbon part.

Heat call: No heat

Do not heat a bike frame. Carbon is damaged by heat, and torch heat can weaken aluminum and steel tubing and their joints.

Safety

Do not clamp a carbon frame or carbon post in a vise. It can crack.
Do not use the saddle as a lever on a carbon post. If it is truly stuck, a bike shop has better tools.

What to Spray