Chain Shifting Off of Lower Cog
03-20-07, 08:34 AM
#1
Senior Member
Thread Starter
Join Date: Mar 2007
Location: Central NC
Posts: 155
Bikes: Dawes LT1000, Mercier Draco
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times
in
0 Posts
Chain Shifting Off of Lower Cog
This doesn't happen often, usually once about every 20-30 mile trip. This happens while downshifting. I believe if it was a shifting error, on my part, it would happen more often. The bike is new, with 8-speed cassett, and the deraileurs were adjusted by the LBS. The shifters are Shimano 2203 "thumb" shifters, and they shift perfectly, spot on with no chatter, but I can't figure out why the occasional jump. Any clues or suggestions, or is it just the nature of the beast?
Thanks,
Mike
Thanks,
Mike
03-20-07, 08:49 AM
#3
Senior Member
Thread Starter
Join Date: Mar 2007
Location: Central NC
Posts: 155
Bikes: Dawes LT1000, Mercier Draco
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times
in
0 Posts
Originally Posted by barba
It sounds like the limit screw on the rear derailleur is not set correctly allowing the chain to over shift.
Mike
03-20-07, 02:08 PM
#4
Really Old Senior Member
Sometimes it just happens. Are you shifting front & back at the SAME time? That can have a "snap the whip" effect on the chain.
A large difference in tooth count between small and larger chain ring could exacebate any problem.
WHAT I would look for first however, is possible stiff chain link(s). Hold the rear wheel off the ground and slowly crank. Look at the jockey pulleys on the Rder for a "jump" as a bad link passes through them.
A large difference in tooth count between small and larger chain ring could exacebate any problem.
WHAT I would look for first however, is possible stiff chain link(s). Hold the rear wheel off the ground and slowly crank. Look at the jockey pulleys on the Rder for a "jump" as a bad link passes through them.
03-20-07, 06:15 PM
#5
Senior Member
Thread Starter
Join Date: Mar 2007
Location: Central NC
Posts: 155
Bikes: Dawes LT1000, Mercier Draco
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times
in
0 Posts
Thanks, Bill. I didn't think about stiff links. I'll check it out.
Mike
Mike
03-21-07, 09:54 AM
#6
Elitist Troglodyte
Join Date: Jun 2006
Location: Dallas
Posts: 6,925
Bikes: 03 Raleigh Professional (steel)
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 2 Post(s)
Likes: 0
Liked 1 Time
in
1 Post
Check that your dérailleur hanger isn't bent. Both idler wheels should be in the plane of the cogs.
__________________
Stupidity got us into this mess - why can't it get us out?
- Will Rogers
Stupidity got us into this mess - why can't it get us out?
- Will Rogers
03-21-07, 11:19 AM
#7
Senior Member
Thread Starter
Join Date: Mar 2007
Location: Central NC
Posts: 155
Bikes: Dawes LT1000, Mercier Draco
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times
in
0 Posts
Thanks DMF. Everything seems to check out. I'm beginning to wonder if it IS shifting error, on my part! It seems to happen at the end of my ride, when I'm starting to get tired 
I'm going to pay more attention to my shift combinations, from here on out. BTW, I'm just getting back into cycling, and the integrated brake/shifters is a different feel, for me. I DO like them, however. They're alot more precise than the 'ol stem mounted shifters that I grew up with.
Mike
I'm going to pay more attention to my shift combinations, from here on out. BTW, I'm just getting back into cycling, and the integrated brake/shifters is a different feel, for me. I DO like them, however. They're alot more precise than the 'ol stem mounted shifters that I grew up with. Mike
