Rear cogs clatter and shift by themselves.

Forum guidelines BT super discount
General Discussion Triathlon Talk » Rear cogs clatter and shift by themselves. Rss Feed  
Moderators: k9car363, alicefoeller Reply
2011-02-13 6:25 PM

User image

Master
1929
100050010010010010025
Midlothian, VA
Subject: Rear cogs clatter and shift by themselves.
Last week I was cleaning my chain and such and I noticed my gears were starting to clatter a bit.  I think I fiddled with everything a little too much.  I even had a more experienced rider help out at a training session.

Well, I THOUGHT all was good until I went out for some rides yesterday and today.

When going up steep hills, in my last 'granny' gear the darn thing will jump to the next gear.  Not cool. I usually stay seated, but if it did that while I was standing up it would not be pretty to say the least.

I'm thinking it has something to do with the barrel adjuster, but I can't figure out what to do with it. Which way to turn and how much?  Just when I think I have it, I notice it now jumps around on the smaller gears.  So I can get one end or the other to behave well, but not ALL of them.

I am pretty sure I have the limits set right, but I'm starting to think there is some combination of adjustments out of whack.

Shimano Ultegra on a 2011 Felt B16
53/39
12/25 cassette

Thanks for any help,

-eric

2011-02-13 6:56 PM
in reply to: #3353156

User image

Pro
4360
200020001001001002525
Baton Rouge area
Subject: RE: Rear cogs clatter and shift by themselves.
Check out:
http://www.sheldonbrown.com/derailer-adjustment.html

or
a month or two ago Bicycling magazine had an article on adjusting your deraileur. 
2011-02-13 7:22 PM
in reply to: #3353192

User image

Sensei
Sin City
Subject: RE: Rear cogs clatter and shift by themselves.
There is a small black dial (maybe silver) that is located where the cable connects to the rear derailure.  You can twist this to fine tune the deraileur.

Try to notice if the gears skip up a cog, or down, that will tell you wich way it needs to be adjusted.  What I do, is put the chain in the big ring up front, and set the chain to the 3 cog from the small end on the back.  If you twist the dial, you will notice that EVER SO SLIGHTLY, the derailure will move to the left or right.  I adjust it so the small pully/cogs in the deraileur, line up EXACTLY with the cogs on the cassette.

SIDE NOTE, check to see if you bent your deraileur or deraileur hanger slightly during all your fidgeting.  Most like not the case, but something to look at.

I didn't look at the above noted videos, so they may give a good example on how to do it.

If that fails, take it to your LBS.  Often, they may be willing to make a small adjustments like that for free and on the spot.

Edited by Kido 2011-02-13 7:23 PM
New Thread
General Discussion Triathlon Talk » Rear cogs clatter and shift by themselves. Rss Feed