See also also bike pic for other bike-related technical discussions and more failed parts.

Lubricate Seat Posts and Quill Stems Annually

Seatposts need to be lubricated where they go in the frame, and also need to be removed and re-lubricated annually. Without this, the seatpost can sieze in place, requiring a saw and labor to remove it.

From and as of 2012/06. This is a post which was on the way to siezing but had not yet fully siezed.

[stukmk1.jpg]   [stukmk2.jpg]  

Seatposts sieze this way due to a combination of design choices.

Quill-style stems have the same problem: the stem is held at the bottom and can wiggle at the top. They also sieze in place if not lubricated periodically. Ahead-style stems do not typically have this problem, though some "art" designs may.

The usual solution to the seatpost siezing problem is to simply remove the seatpost annually and lubricate it. Lubrication reduces wear and slows oxygen intrusion. However, enough lubricant is pressed out over time that the post will sieze if the lubricant is not replenished occasionally.

The joint could be redesigned to prevent sticking without annual maintenance. But most designs introduce new problems that have so far discouraged adoption. For example:

Removing and relubricating the post is quick, so the main disadvantage of the "annual maintenace" approach is many riders are not aware of the problem and thus not aware of the need for maintenance. The above bicycle was assembled without lubricating the seatpost, and was ridden for about a year.

Related photos from as of 2012/06:


As noted above, quill stems also sieze.

[stem9r2.jpg]   [stem9r1.jpg]   [stem9r3.jpg]   [stem9r4.jpg]