How to Replace a Bicycle Stem - Quill Stems
Why Bicycles Stack Exchange recommends it
Bicycles Stack Exchange answerers point people to it when someone has a stuck or loose quill stem, or a handlebar that rotates on its own, and needs a clear demonstration of how the wedge and bolt work.
Recommended by 3 people across 3 different months, 2019 to 2022.
What it is
A Park Tool repair tutorial on removing and installing a quill stem on a bicycle. It covers choosing compatible parts, freeing a stuck quill, and the final centering and torquing steps, with chapters for preliminary info, removal and installation.
What people said
Recommends Andrew Henle · 2019-11 · Bicycles Stack Exchange · on “Used WD-40 on headset and now it loosens daily”
Using WD40 on a headset should not cause it to loosen. Something else is wrong. You need to find out what that is. First - don't ride the bicycle until the problem is identified and fixed. Doing so might be dangerous - both to you and anyone near, as you may lose control. If your bicycle has a new-style "threadless" headset [LINK] , the stem bolts may be undertorqued. Or, they may have been overtorqued in the past and crushed the steer tube that the stem clamps on to so that it no longer stays tight. Those are by far the two most likely problems with a headset that won't stay tight. Park Tool has a series of good videos on bicycle maintenance. This one is for troubleshooting a headset: What
Recommends Argenti Apparatus · 2020-01 · Bicycles Stack Exchange · on “Handle bar rotates on its own. Can’t screw the screw all the way down”
Older bikes have what is known as a quill stem . The stem telescopes inside the fork steerer tube and is held in place with a wedge. The long bolt you removed threads into the wedge. When the bolt is tightened the wedge is pulled up. What you should have done is loosened the bolt, aligned the bars and re-tightened the bolt. With the bolt removed the wedge is not longer attached to the stem. It's either dropped down lower in the head tube or is stuck where it was. You should be able to get the wedge out. Out the stem and look in the head tube with a flashlight. It may simply drop out if you turn the bike upside down, or you can tap it loose with a hammer and long screwdriver or the bolt itsel
Recommends Jeff · 2022-02 · Bicycles Stack Exchange · on “Will it be effective to use hot water and cold canned air to unjam a quill stem?”
Welcome to Bicycle Stack Exchange. A quill stem is typically held in place by the interference fit of a separate wedge-like piece that is attached via a long bolt through the quill stem. See photo below. You can access the head of the bolt on top of the stem. Tightening this bolt draws up the wedge causing it to start sliding by the bottom of the stem. The assembly then becomes "jammed" (fixed in place) in the fork steerer tube. When you loosen the stem bolt, the bolt will begin to rise up out of the stem as it moves up the threads of the wedge. The wedge usually remains fixed in the jammed position and nothing is loosened up but the bolt. When the bolt comes up a centimeter or two above the