Chain Keeps Falling Off, help?
05-26-13, 06:37 AM
#1
Senior Member
Thread Starter
Join Date: Jan 2013
Location: Amherst, MA
Posts: 205
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 7 Post(s)
Likes: 0
Liked 0 Times
in
0 Posts
Chain Keeps Falling Off, help?
The chain always falls off toward the bike frame, off of the smaller front cog.
It's likely not the rear derailleur since I'm usually in the middle rear cog.
It might be the front derailleur since when I put it as close to the chain as possible, the chain doesn't fall. This is again, on the third cog up in the rear and the smaller cog in front.
That said, doing the above might just be preventing the chain from falling because of its potential real problem: chain, crank set, or cassette wear.
What are your opinions?
It's likely not the rear derailleur since I'm usually in the middle rear cog.
It might be the front derailleur since when I put it as close to the chain as possible, the chain doesn't fall. This is again, on the third cog up in the rear and the smaller cog in front.
That said, doing the above might just be preventing the chain from falling because of its potential real problem: chain, crank set, or cassette wear.
What are your opinions?
05-26-13, 07:19 AM
#2
Really Old Senior Member
05-26-13, 07:20 AM
#3
Senior Member
Join Date: Oct 2011
Location: Normal, Illinois
Posts: 2,714
Bikes: Trek 600 ,1980Raleigh Competition G.S., 1986 Schwinn Passage, Facet Biotour 2000, Falcon San Remo 531,Schwinn Sierra, Sun Seeker tricycle recumbent,1985 Bianchi Squadra
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 33 Post(s)
Liked 12 Times
in
9 Posts
Check and make sure all of your cog bolts are tight, and that your small cog is not bent in some way, then, if that's not the case, check your FD limit screw, and position of the FD to the cogs, angle and height. This will get you started.
05-26-13, 08:23 AM
#5
Senior Member
Join Date: Sep 2010
Location: Roswell, GA
Posts: 8,319
Bikes: '93 Trek 750, '92 Schwinn Crisscross, '93 Mongoose Alta
Mentioned: 30 Post(s)
Tagged: 0 Thread(s)
Quoted: 1438 Post(s)
Liked 1,090 Times
in
722 Posts
You should of course make sure that your derailleur is set up properly as advised above, but if would like to install a chain catcher anyway (I always do) I recommend the N-Gear Jump Stop®, if it will fit your frame.
05-26-13, 12:06 PM
#6
Senior Member
Join Date: Apr 2009
Location: New Rochelle, NY
Posts: 37,898
Bikes: too many bikes from 1967 10s (5x2)Frejus to a Sumitomo Ti/Chorus aluminum 10s (10x2), plus one non-susp mtn bike I use as my commuter
Mentioned: 134 Post(s)
Tagged: 1 Thread(s)
Quoted: 5352 Post(s)
Liked 1,792 Times
in
1,016 Posts
The first step is to determine if the FD itself is causing the chain to fall off. If the outer plate of the FD is touching the chain when on the granny and inner half of the cassette, then you have an FD adjustment issue, most likely the inner limit screw. It could also be a trim issue (cable length adjustment) if the shifting and trim on other chainrings isn't spot on.
If the FD isn't touching the chain, and the only way to prevent it from coming off to the inside is to have the FD keep it on with the inner cage plate, then you have a sprocket problem, most likely a single bend or dinged tooth.
Either way the first step is to determine why the chain is coming off, and pinning it either on the FD or the sprocket engagement. It's also possible that a damaged link in the chain itself is part of the problem, but this is comparatively rare, and my money is on the FD trim.
If the FD isn't touching the chain, and the only way to prevent it from coming off to the inside is to have the FD keep it on with the inner cage plate, then you have a sprocket problem, most likely a single bend or dinged tooth.
Either way the first step is to determine why the chain is coming off, and pinning it either on the FD or the sprocket engagement. It's also possible that a damaged link in the chain itself is part of the problem, but this is comparatively rare, and my money is on the FD trim.
__________________
FB
Chain-L site
An ounce of diagnosis is worth a pound of cure.
“Never argue with an idiot. He will only bring you down to his level and beat you with experience.”, George Carlin
“One accurate measurement is worth a thousand expert opinions” - Adm Grace Murray Hopper - USN
WARNING, I'm from New York. Thin skinned people should maintain safe distance.
FB
Chain-L site
An ounce of diagnosis is worth a pound of cure.
“Never argue with an idiot. He will only bring you down to his level and beat you with experience.”, George Carlin
“One accurate measurement is worth a thousand expert opinions” - Adm Grace Murray Hopper - USN
WARNING, I'm from New York. Thin skinned people should maintain safe distance.
Thread
Thread Starter
Forum
Replies
Last Post
johnyguy
Road Cycling
19
09-20-15 03:57 PM
LeicaLad
Bicycle Mechanics
22
01-22-15 09:31 PM
