Bicycle TutorBicycle Tutor

Show off your bike!

Post Reply 

Derailleur cable adjustment

Related video tutorials:
How to Adjust Your Front Derailleur How to Adjust Your Front Derailleur
* Now with 3D interactive instructions
Author Message
Bob K Denver Offline
Member


Posts: 10
Joined: May 2010
Post: #1
Derailleur cable adjustment
Adjusting derailleur cable tension, I am curious why compressing the housing tightens the cable and therefore moves the derailleur. Please explain the mechanics.
Sep 24, 2012 08:10 AM
Find all posts by this user Quote this message in a reply
DaveM Offline
Veteran Member


Posts: 1,296
Joined: Aug 2008
Post: #2
RE: Derailleur cable adjustment
The term "adjusting the cable tension" isn't really accurate. When you turn the adjuster barrels, you're actually making the housing longer or shorter (not by compressing the housing, but by making the adj barrel itself longer or shorter). In effect, you're making the path that the cable has to follow to get to the derailleur longer or shorter. The length of the path of the cable will change where the derailleur sits for a given shifter position. The actual tension on the cable is just a function of the strength of the spring in the derailleur. I'm not sure why this became the conventional term for the adjustment.
Sep 24, 2012 09:11 AM
Visit this user's website Find all posts by this user Quote this message in a reply
Bob K Denver Offline
Member


Posts: 10
Joined: May 2010
Post: #3
RE: Derailleur cable adjustment
(Sep 24, 2012 09:11 AM)DaveM Wrote:  The term "adjusting the cable tension" isn't really accurate. When you turn the adjuster barrels, you're actually making the housing longer or shorter (not by compressing the housing, but by making the adj barrel itself longer or shorter). In effect, you're making the path that the cable has to follow to get to the derailleur longer or shorter. The length of the path of the cable will change where the derailleur sits for a given shifter position. The actual tension on the cable is just a function of the strength of the spring in the derailleur. I'm not sure why this became the conventional term for the adjustment.

Thank you. Please clear it up a little more. I understand you are saying when the barrel adjuster is turned counterclockwise it lengthens the barrel, so the cable has further to travel. But how does it travel further and tension more, when it seems as though the cable is just passing through the barrel? Does the shape of the housing stay the same?
Sorry for all of the questions, just trying to understand.
Sep 24, 2012 10:03 AM
Find all posts by this user Quote this message in a reply
DaveM Offline
Veteran Member


Posts: 1,296
Joined: Aug 2008
Post: #4
RE: Derailleur cable adjustment
The housing itself does not change. On most adjusting barrels, there are two parts with one threaded inside the other. When you turn it, the inner part threads out of the outer part making the part's overall length longer. Look closely as you turn it, you should be able to see what changes.
Sep 24, 2012 10:15 AM
Visit this user's website Find all posts by this user Quote this message in a reply
Bob K Denver Offline
Member


Posts: 10
Joined: May 2010
Post: #5
RE: Derailleur cable adjustment
(Sep 24, 2012 10:15 AM)DaveM Wrote:  The housing itself does not change. On most adjusting barrels, there are two parts with one threaded inside the other. When you turn it, the inner part threads out of the outer part making the part's overall length longer. Look closely as you turn it, you should be able to see what changes.

So the housing does not change, the cable tension does not change, but making the barrel longer, the cable pulls on the derailleur, making it move. Do I have it, and thank you?
Sep 24, 2012 11:09 AM
Find all posts by this user Quote this message in a reply
nfmisso Offline
Veteran Member

San Jose, CA
Posts: 2,047
Joined: Jul 2010
Post: #6
RE: Derailleur cable adjustment
(Sep 24, 2012 11:09 AM)Bob K Denver Wrote:  So the housing does not change, the cable tension does not change, but making the barrel longer, the cable pulls on the derailleur, making it move. Do I have it, and thank you?

Yes

Nigel
Sep 24, 2012 12:53 PM
Find all posts by this user Quote this message in a reply
Post Reply 


Possibly Related Threads...
Thread: Author Replies: Views: Last Post
  Trouble with chain & rear derailleur pulleys generic_cyclist 5 397 Apr 11, 2014 10:35 PM
Last Post: generic_cyclist
  Front derailleur dakawan 3 346 Apr 5, 2014 01:18 PM
Last Post: dakawan
  Shimano TX35 Rear Derailleur Ebernal32 5 375 Apr 3, 2014 12:11 PM
Last Post: Ebernal32
  Rear shifter not connected to tensioned cable? insurgasaurus 5 413 Mar 31, 2014 10:00 AM
Last Post: insurgasaurus
  Rear derailleur problem, chain rubbing the lower pulley cage grandmaster 15 1,185 Mar 18, 2014 07:54 PM
Last Post: grandmaster
  Tiagra Rear Derailleur Won't Shift CheddarExpress 2 678 Feb 20, 2014 12:33 AM
Last Post: Joe_W
  Cable on front derailleur keeps getting damaged BigRiz 2 599 Feb 9, 2014 09:17 AM
Last Post: BigRiz
  Rear Deraileur Cable RunningBehind 9 928 Feb 4, 2014 01:18 PM
Last Post: GeorgeET
  SRAM X0 trigger shifter with Shimano Front Derailleur? gregw 6 1,780 Jan 28, 2014 07:58 PM
Last Post: gregw
  Shimano 105 - Rear Derailleur Problem RunningBehind 7 1,480 Jan 27, 2014 05:48 PM
Last Post: RunningBehind

Forum Jump:


RSS Forum RSS Feeds / Powered by MyBB

ISSN 1918-3445 © Copyright 2007-2010 Bicycle Tutor / Privacy Policy

feed