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

Hanger being pulled every couple revolutions

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.

Hanger being pulled every couple revolutions

Old 06-20-10, 07:25 PM
  #1  
sleizure
Senior Member
Thread Starter
 
Join Date: Oct 2008
Location: Vancouver, BC
Posts: 87

Bikes: Surly LHT 54cm, Thorn Nomad Mk2

Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
Hanger being pulled every couple revolutions

Yesterday when I pulled into Yellowknife after traveling over 900km through rugged gravel terrain I got excited, took a photo of my bike next to the welcome sign and moved forward. Shortly there after I noticed a strange problem when pedalling, I noticed my hanger was being pulled forward every couple pedal revolutions in certain gears. It's a holiday here and no bike shops open for the next 2 days. Any quick hints on where I could be looking?
sleizure is offline  
Old 06-20-10, 07:33 PM
  #2  
Asi
Engineer
 
Asi's Avatar
 
Join Date: May 2010
Location: Bucharest, Romania, Europe
Posts: 591

Bikes: 1989 Krapf (with Dura-ace) road bike, 1973 Sputnik (made by XB3) road bike , 1961 Peugeot fixed gear, 2010 Trek 4400

Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 38 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
hanger? or the cage of pulleys in the RD?
The hanger is the solid eyelet that is bolted to the frame and supports the RD.

My bet is that you have a stiff link in the chain.

From Sheldon Brown: http://www.sheldonbrown.com/derailer-adjustment.html

Stiff links

If you have a regular, repeating skip or hitch every 3 or 4 turns of the pedals, you may have a stiff chain link. This is commonly the link where the chain was joined when it was installed. When the chain tool presses the pin through the chain, the head of the pin tends to pull the uppermost chain plate along with it, so that the two outer plates are squeezing together against the inner plates. The easiest way to fix this is to bend the problem area of the chain into a "Z" shape, with the bad joint on the diagonal part, then flex the chain back and forth. This will slightly spread the tight plates, and free up the link.
If your chain has a link that has been bent in a chain-jamming incident, it can cause similar symptoms. Generally, the bent link (or the whole chain) will need to be replaced.
The easiest way to spot stiff/damaged links is to shift the bike into the small/small gear (the gear you should never actually ride in.) This gear has the chain at its slackest, and flexes it farther than any other gear, as it goes around the small rear sprocket and the derailer pulleys. Slowly backpedal while watching the chain as it feeds through the rear derailer, and you will usually be able to see the bad link jump.
also check: http://bicycletutor.com/stiff-chain-link/

Last edited by Asi; 06-20-10 at 07:47 PM.
Asi is offline  
Old 06-20-10, 09:33 PM
  #3  
sleizure
Senior Member
Thread Starter
 
Join Date: Oct 2008
Location: Vancouver, BC
Posts: 87

Bikes: Surly LHT 54cm, Thorn Nomad Mk2

Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
Thank you - It's likely I bashed the chain. Will review this tommorrow morning and see if I can resolve with a pair of pliers!
sleizure is offline  

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


Thread Tools
Search this Thread

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

Copyright 2018 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.