~craftyguy/blog.craftyguy.net

5522195a13a305b7ef68d8398cfed34078294283 — Clayton Craft 4 months ago 8ae46b3
content/2021-05-23-bottom-bracket-remove: new post
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title = "On removing a stubborn square tapered bottom bracket"
date = 2021-05-22
[taxonomies]
tags = ["cycling"]
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I recently acquired enough quality parts to upgrade my road bike's drivetrain
from 9 speed to 10 speed. It couldn't have come at a better time too, my old
bottom bracket was starting to get that hallmark 'coffee grinder' sound to it. 

Of course the old bottom bracket was more difficult to remove than every online
tutorial would have you believe. The hosts of these videos must be some of the
strongest people alive, or they're working with some perfect setup where the
bottom bracket was installed minutes before and has never been used. You know
what I am talking about.

{{ resize_image_fit_width(path="../static/images/2021-05-23-bare-bottom-bracket.jpg", width=300) }}

In the real world, bottom brackets are a pain in the ass to remove. The area
that the bottom bracket tool has to grip the bottom bracket is often shallow,
and tool slippage is a real challenge. It can do things like damage threads in
the frame (or so I've heard, I've luckily never accomplished this), and cause
you to accidentally grind your knuckles on things (I wish I were going off of
rumors on that one.)

{{ resize_image_fit_width(path="../static/images/2021-05-23-tool-on-bb.jpg", width=300) }}

I figured out a neat trick with my particular bottom bracket tool to remove the
old square tapered bottom bracket using no extra parts, except for a washer
added for good measure.  Here are all the parts you need:

{{ resize_image_fit_width(path="../static/images/2021-05-23-parts.jpg", width=300) }}

The bolt is the dust cover bolt from the cranks, that screws directly into the
threads at the end of the square taper. The bolt is long enough to reach the
threads with enough room to spare, even when inserted into the tool. I added a
washer because the diameter of the bolt head is just barely larger than the
tool opening, and I didn't want it to pop off unexpectedly when I was giving it
my all. If the bolt isn't long enough, find one that is with the same threading
as the original bolt!

{{ resize_image_fit_width(path="../static/images/2021-05-23-tool-secured-bb.jpg", width=300) }}

Don't get too crazy tightening the bolt, I just used my hand to tighten it. The goal is to have the tool held tight to the bottom bracket. With the tool securely fastened to the bottom bracket, it's time to get to wrenchin':

{{ resize_image_fit_width(path="../static/images/2021-05-23-wrenching-tool.jpg", width=300) }}

After cleaning off the threads in the frame, it is now ready to accept a new bottom bracket!
{{ resize_image_fit_width(path="../static/images/2021-05-23-naked-frame.jpg", width=500) }}

A static/images/2021-05-23-bare-bottom-bracket.jpg => static/images/2021-05-23-bare-bottom-bracket.jpg +0 -0
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A static/images/2021-05-23-parts.jpg => static/images/2021-05-23-parts.jpg +0 -0
A static/images/2021-05-23-tool-on-bb.jpg => static/images/2021-05-23-tool-on-bb.jpg +0 -0
A static/images/2021-05-23-tool-secured-bb.jpg => static/images/2021-05-23-tool-secured-bb.jpg +0 -0
A static/images/2021-05-23-wrenching-tool.jpg => static/images/2021-05-23-wrenching-tool.jpg +0 -0