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

Chain keeps dropping.

Notices
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.

Chain keeps dropping.

Old 03-26-10, 02:20 AM
  #1  
robertv
Senior Member
Thread Starter
 
Join Date: Jun 2009
Posts: 438
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 1 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
Chain keeps dropping.

So, I've got a surly crosscheck, totally stock with a double in the front and bar end shifters, the rear deraileur is tiagra. I've just started working as a courier and when I hop up a curb too quickly, or down a curb, or just throw the bike around a bit the chain drops off. This only happens when I'm in the little ring. It seems to me like this might mean the derailleur isn't tensioned enough, but I really don't know. It shifts through the gears fairly flawlessly. This is a pretty big issue as I do a lot of jumping up and down curbs over the work day, and I do get sick of putting the chain back on. I'm also worried that I might not notice it pop off as I rush into traffic and I'll get run over. Any advice? The guys I work with, even the ones with geared bikes, don't seem to know or care too much about mechanical issues. Most suggested just running a single up front, although I think the derailleur would still need to be tensioned properly. So any ideas? If I hold the bike in the air and shake it up and down hard the chain also pops up.
robertv is offline  
Old 03-26-10, 02:35 AM
  #2  
operator
cab horn
 
Join Date: Jun 2004
Location: Toronto
Posts: 28,353

Bikes: 1987 Bianchi Campione

Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 42 Post(s)
Likes: 0
Liked 23 Times in 17 Posts
1) Check that the chain is the proper (shortest) length
2) Check that the B-tension adjustment on the derailleur is optimal
3) Check that the limit screws for front and rear derailleurs are adjusted properly, in particular the low limit for the front derailleur is as close to the chain as possible with no rub while not affecting shifts (in the small ring/biggest cog combo).
4) Consider installing a chain catcher/keeper.
5) Consider learning to drop off curbs without a significant impact. This is riding style.

operator is offline  
Old 03-26-10, 02:46 AM
  #3  
robertv
Senior Member
Thread Starter
 
Join Date: Jun 2009
Posts: 438
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 1 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
Ok, Your advice is good, but...
1) how do I do that? The chain is stock, I imagine surly put the optimal chain on it, if it isn't, how do I tell?
2) How do I do that and define optimal? really dumb the explanation down for me cause I'm ham-handed and tend to break little mechanical doodads.
3)rear derailleur seems adjusted properly as it shifts well and doesn't over shift. Front derailleur is on friction shift, but I don't think the limits are the issue, the chain comes off the bottom of the chainring, but I'll look at that anyway.
4)will do.
5) I do try to do this, in fact I do these things all softly enough that my u-lock doesn't fly out of my back pocket. Yet the chain does pop off. it even pops off if I hop off the bike then quickly lift the bike up and put it down against a wall. It's beginning to piss me off.
robertv is offline  
Old 03-26-10, 02:54 AM
  #4  
operator
cab horn
 
Join Date: Jun 2004
Location: Toronto
Posts: 28,353

Bikes: 1987 Bianchi Campione

Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 42 Post(s)
Likes: 0
Liked 23 Times in 17 Posts
1) https://www.parktool.com/repair/readhowto.asp?id=26
2) https://www.parktool.com/repair/readhowto.asp?id=64

Use the big/big method + 1 link. Don't assume anything about factory assemblies or shop final assembly quality.
operator is offline  
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
banaeatingbiker
Bicycle Mechanics
9
09-10-17 08:52 PM
Roll-Monroe-Co
Bicycle Mechanics
11
06-09-16 01:42 PM
CompleteStreets
Bicycle Mechanics
6
04-17-16 02:08 PM
Indicud
Bicycle Mechanics
5
12-12-12 10:19 PM
bobonker
Bicycle Mechanics
2
09-27-12 02:51 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


Thread Tools
Search this Thread

Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service - Do Not Sell My Personal Information -

Copyright 2021 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.