Go Back  Bike Forums > Bike Forums > Bicycle Mechanics
Reload this Page >

ready to change out chainring, but...

Bicycle Mechanics Broken bottom bracket? Tacoed wheel? If you're having problems with your bicycle, or just need help fixing a flat, drop in here for the latest on bicycle mechanics & bicycle maintenance.

ready to change out chainring, but...

Old 09-28-10, 11:54 AM
Senior Member
Thread Starter
Join Date: Apr 2005
Location: Missoula, Montana
Posts: 700

Bikes: Trek Domane SL5, Trek Checkpoint SL5, Cannndale Trail SE 4, Specialized Langster

Liked 137 Times in 73 Posts
ready to change out chainring, but...

Based on advice given here, I decided to change a 30t chainring for a 24t to get some lower gears. I just received the chainring, but before I dive into removing the crank and chainring, I have a few questions concerning this Octalink bottom bracket and crank.

1. Do I need any special tools? I can see an allen bolt which looks like 10mm. i can get a wrench at the local hardware store. Anything I should be aware of?

2. I have an old crank removal tool from twenty years ago. will that work or will I have to buy something new? If the latter, what?

3. After the crank is off, I will unbolt the inner chainring and replace with 24t. anything I should be aware of?

4. Will I have to move/adjust the front derailleur or replace it?

5. Anything else I should know about.

Thanks for the help.
jackb is offline  
Old 09-28-10, 12:25 PM
Join Date: Jun 2010
Location: NW,Oregon Coast
Posts: 43,595

Bikes: 8

Liked 1,361 Times in 867 Posts
Hardware stores have Metric allen wrenches I have an 8mm allen as my crank arm fixing bolt,
but I cannot see yours.

The Octalink is a bigger tube than the square taper , you need a new crank arm extractor tool.

IF there are 2 little pin spanner holes in a ring around the bolt head

you may have a self extracting bolt . the ring screws into the place where the extractor may
be threaded into , It should come out with out another tool..

[carefull I've had a self extractor strip the crankarm and not budge ]

If there is a black plastic ring around the bolt Its not self extracting..

You should not have to remove the FD.
if you are not changing the big ring..

you will need a 5mm allen to take off the third ring mounting bolts.

Last edited by fietsbob; 09-28-10 at 12:28 PM.
fietsbob is offline  
Old 09-28-10, 07:40 PM
John Wayne Toilet Paper
nhluhr's Avatar
Join Date: Feb 2006
Location: Roanoke
Posts: 1,952

Bikes: BH carbon, Ritchey steel, Kona aluminum

Liked 0 Times in 0 Posts
There is a tool made by shimano that is used to screw in those self-extractor nuts AND to hold chainring nuts. It makes it a lot easier to work on cranks but you can get by without it.

Shimano TL-FC21

Self-Extractor Crank Bolt:

Non-self-extracting bolt:

If you have and will use the self-extractor function, make sure the nut is screwed all the way into the crank-arm before you start unscrewing the bolt, or else the lack of thread engagement in the arm may strip the self-extractor out of the arm and damage threads on one or the other. When you put it back together, clean and re-grease all the surfaces that will touch inside. Make sure you tighten the self-extractor down all the way (with the washer in between) after you tighten the crank bolt.
nhluhr is offline  
Related Topics
Thread Starter
Last Post
Bicycle Mechanics
06-08-18 11:11 AM
Classic & Vintage
07-02-16 02:22 PM
Bicycle Mechanics
03-07-13 09:40 PM
Bicycle Mechanics
02-03-10 03:52 PM

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off

Thread Tools
Search this Thread

Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service - Your Privacy Choices -

Copyright © 2024 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.