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

FD pivots worn out?

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.

FD pivots worn out?

Old 04-07-18, 03:10 AM
  #1  
Medic Zero
Senior Member
Thread Starter
 
Medic Zero's Avatar
 
Join Date: Apr 2011
Location: Vancouver,Washington
Posts: 2,286

Bikes: Old steel GT's, for touring and commuting

Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 38 Post(s)
Likes: 0
Liked 1 Time in 1 Post
FD pivots worn out?

.

Curious about the signs and symptoms of front derailleur pivots being worn out.

I never would've thought it really being a possibility, but I once had a bike mechanic I trusted helping me build up a used bike and he said that was the case with the FD, so I swapped it for one from my parts pool.

Now, on my commuter, I've been having problems where the bike shifts itself into the smallest chainring and when I try and shift it back up it won't stay there. Acts like there is a spring or tension pulling it back down. Sometimes, if I hold the (friction) shifter in place, in the position of the middle or large chainring, it'll stay, sometimes (usually) it won't.

I've tried replacing the cable and housing, because at first I thought the shifter had ingested a bit of rubber band, and that was causing it, but the problem persists with the new cable and housing and a thorough cleaning of the shifter, although I suppose there's a small possibility that there is a bit of rubber hiding in there causing the issue.

Friction shifting, triple, bottom pull. Don't recall the provenance of this particular derailler from my parts pool, but it was used before I started using it, and I've put right about 5,000 miles on it since then. It worked fine for first couple of years of those miles. FWIW, I shift a LOT.

Is there any other possiblity here, or is it just time for a new FD?


Many thanks!
Medic Zero is offline  
Old 04-07-18, 05:50 AM
  #2  
dsbrantjr
Senior Member
 
dsbrantjr's Avatar
 
Join Date: Sep 2010
Location: Roswell, GA
Posts: 7,438

Bikes: '93 Trek 750, '92 Schwinn Crisscross, '93 Mongoose Alta

Mentioned: 22 Post(s)
Tagged: 0 Thread(s)
Quoted: 1109 Post(s)
Liked 494 Times in 360 Posts
It sounds like you are having a problem with your shifter not staying in place, not with the derailleur. Most of them have an adjustment screw which needs to be tightened to hold the shifter setting. This screw often needs a lot of force to tighten it sufficiently. Many friction shifters have small plastic parts inside, one of which may be defective.
dsbrantjr is offline  
Old 04-07-18, 06:24 AM
  #3  
cny-bikeman 
Mechanic/Tourist
 
Join Date: Apr 2007
Location: Syracuse, NY
Posts: 7,510

Bikes: 2008 Novara Randonee - love it. Previous bikes:Motobecane Mirage, 1972 Moto Grand Jubilee (my fave), Jackson Rake 16, 1983 C'dale ST500.

Mentioned: 10 Post(s)
Tagged: 0 Thread(s)
Quoted: 481 Post(s)
Likes: 0
Liked 3 Times in 3 Posts
Agreed. The derailleur stays in place for as long as it is held there by the cable. Worn pivots (very rare) would only affect the efficiency of shifting.
__________________
There's no such thing as a routine repair.

Don't tell me what "should" be - either it is, it isn't, or do something about it.

If you think I'm being blunt take it as a compliment - if I thought you were too weak to handle the truth or a strong opinion I would not bother.

Please respect others by taking the time to post clearly so we can answer quickly. All lowercase and multiple typos makes for a hard read. Thanks!

Last edited by cny-bikeman; 04-07-18 at 07:57 AM.
cny-bikeman is offline  
Old 04-07-18, 07:12 AM
  #4  
Hoopdriver
On Holiday
 
Hoopdriver's Avatar
 
Join Date: Apr 2017
Posts: 1,014

Bikes: A bunch of old steel bikes

Mentioned: 14 Post(s)
Tagged: 0 Thread(s)
Quoted: 393 Post(s)
Likes: 0
Liked 7 Times in 6 Posts
Should be pretty easy to see slop due to worn pivots; however I would think that other reasons are more likely for your issue. Assuming that your shifters are functioning correctly, a FD with worn pivots would still stay where you put it.

I wonder how frequent pivots wear out in FDs anyway. Unless you are set up for half-step shifts (a pattern that I really have learned to appreciate), the FD gets only a small proportion of use compared to the RD.

Try a different shifter to see what happens. Also curious to your reference of rubber bands - I have no idea what this is about. Where would these rubber bands come from?
Hoopdriver is offline  
Old 04-07-18, 07:17 AM
  #5  
dsbrantjr
Senior Member
 
dsbrantjr's Avatar
 
Join Date: Sep 2010
Location: Roswell, GA
Posts: 7,438

Bikes: '93 Trek 750, '92 Schwinn Crisscross, '93 Mongoose Alta

Mentioned: 22 Post(s)
Tagged: 0 Thread(s)
Quoted: 1109 Post(s)
Liked 494 Times in 360 Posts
Originally Posted by Hoopdriver View Post
...Where would these rubber bands come from?
An improvised repair, trying to make a slipping shifter hold, would be my bet.
dsbrantjr is offline  
Old 04-08-18, 02:04 AM
  #6  
Medic Zero
Senior Member
Thread Starter
 
Medic Zero's Avatar
 
Join Date: Apr 2011
Location: Vancouver,Washington
Posts: 2,286

Bikes: Old steel GT's, for touring and commuting

Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 38 Post(s)
Likes: 0
Liked 1 Time in 1 Post
Originally Posted by Hoopdriver View Post
Should be pretty easy to see slop due to worn pivots; however I would think that other reasons are more likely for your issue. Assuming that your shifters are functioning correctly, a FD with worn pivots would still stay where you put it.

I wonder how frequent pivots wear out in FDs anyway. Unless you are set up for half-step shifts (a pattern that I really have learned to appreciate), the FD gets only a small proportion of use compared to the RD.

Try a different shifter to see what happens. Also curious to your reference of rubber bands - I have no idea what this is about. Where would these rubber bands come from?

My Airzoundz horn is mounted right next to the shifter. The horns mount became worn over time and was loose. I was using a rubber band wrapped around it to hold it in place. This rubber band ran around the front of the shifter unit. Sun and weather did a number on it, and it decayed into pieces, one of which appeared to have been ingested by the shifter. Initially I had hoped that this was the issue. Hate to think it's the nice old Suntour shifter failing, but from everyone's responses (THANKS!) it sounds like that's the issue. I've got some lower quality shifters kicking around in the parts boxes somewhere, I'll dig one of them up this week, and give that a try.

THANKS EVERYONE!





.
Medic Zero is offline  
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
bikebasket
Bicycle Mechanics
1
05-28-18 02:49 AM
hedgehog9
Bicycle Mechanics
12
04-28-18 10:53 AM
jfan
Bicycle Mechanics
4
04-12-18 03:11 PM
vespoli
Bicycle Mechanics
3
08-30-14 02:24 PM
landru
Bicycle Mechanics
11
07-28-11 02:18 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 2018 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.