# Need help with chain dropping off front ring



## tbsurf (Apr 15, 2010)

:confused5espite going back to my LBS a few times to have the front derailleur adjusted, I continue having my chain drop when shifting from the large to the small chain ring. It’s getting so I’m dreading shifting it. The mechanic showed my today how to adjust the front der.; said he could adjust it only slightly without having the chain rub. Could there be another problem other than adjustment? My bike is 2 years old with Ultegra drive train. Thanks in advance, TB


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## iheartbenben (Mar 18, 2011)

Andy, is that you?


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## Kerry Irons (Feb 25, 2002)

*Height and angle*



tbsurf said:


> :confused5espite going back to my LBS a few times to have the front derailleur adjusted, I continue having my chain drop when shifting from the large to the small chain ring. It’s getting so I’m dreading shifting it. The mechanic showed my today how to adjust the front der.; said he could adjust it only slightly without having the chain rub. Could there be another problem other than adjustment? My bike is 2 years old with Ultegra drive train. Thanks in advance, TB


The obvious things to look at are whether the derailleur is the right height (the cage should just barely clear the teeth on the big chain ring when shifting) and the right angle (typically this means the outer cage parallel to the big chain ring). Some mysterious combinations of bike and drive train never can be adjusted to prevent this problem, and for those situations you install a chain catcher.


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## tbsurf (Apr 15, 2010)

Kerry,
Thanks for the idea about the chain catcher. I remember hearing about it when Andy Schleck (?) dropped a chain during the TDF last year. I'll look into it, as I can't seem to get this problem resolved by adjustment. Looks like 10 grams and about a $45 penalty, but it will beat stopping to deal with a dropped chain every other ride.


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## reptilezs (Aug 21, 2007)

how big is the gap for the low limit in the lowest gear? hard to say what the problem is without seeing it but i guess the fd cage is blown open


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## tlg (May 11, 2011)

Take it to a different LBS and get a 2nd opinion. 
Your FD is either out of alignment/adjustment or bent. And your LBS SHOULD be able to correct this.


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## Schneiderguy (Jan 9, 2005)

what cog are you in when you shift? If you are in the big ring and your inside cog (easy gear in back) and shift from the big ring to the small ring you are more likely to drop the chain. I thin this was Andy S's mistake in the TdF. So shift several cogs to the outside of the cassette and then shift from the big ring. But follow the above advice as well.


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## eddie m (Jul 6, 2002)

Get a chain catcher. It's just too hard to get the front derailer adjusted to where it never drops but makes the downshift fast every time. 
Using the big-big combination makes the problem worse, but when I ride hard I sometimes find myself there. It's really frustrating to drop a chain when you are struggling to keep up.

em


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## tlg (May 11, 2011)

eddie m said:


> It's just too hard to get the front derailer adjusted to where it never drops but makes the downshift fast every time.


Not true at all. 
I've adjusted FD's on many bikes both road and mountain, triple and double chainrings. It is not hard to do.


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## tbsurf (Apr 15, 2010)

The chain drops when I am shifting from the large to small ring in front and usually the 2, 3 or 4th largest cogs on the rear. I don't know what "fd cage is blown open" means. Thanks, TB


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## eddie m (Jul 6, 2002)

tbsurf said:


> I don't know what "fd cage is blown open" means. Thanks, TB


What sometimes happens is that after you drop the chain a few times, the sideplates of the derailer start to bend. Once that happens, the cage gets too wide and you need to bend it back. 

em


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## Shinjukan (Aug 22, 2011)

Also don't just focus on the FD cage. Check if your big ring has worn or bent tooth/teeth since you said your ride is 2 years old.


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## MisterMike (Aug 12, 2004)

eddie m said:


> Get a chain catcher. It's just too hard to get the front derailer adjusted to where it never drops but makes the downshift fast every time.
> Using the big-big combination makes the problem worse, but when I ride hard I sometimes find myself there. It's really frustrating to drop a chain when you are struggling to keep up.
> 
> em


+1 (one the chain catcher part). While you could always fiddle with the adjustment there still will be those times a chain can drop. A catcher eliminates those times...period.


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## supraholic (Oct 10, 2010)

Here is something simpler. If your chain is dropping, first check if you are cross chaining. 

Cross chain happens when you shift both FD and RD the same time. 

Once you rule that out then check your trim. There should be a high and low adjustment screws on your FD. Concentrate on the FD. 

MAKE SURE YOUR CABLE TENSION IS NOT LOOSE!


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## Bluffplace (Jul 30, 2008)

If your looking for a chain catcher. Take a look at this. Terry is selling them for $25

They're Back - Chaincatchers, that is...: Classifieds: Slowtwitch Forums


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## tbsurf (Apr 15, 2010)

Went to the LBS today and got the chain catcher. Seems like an easy solution. Thanks to all for the help, TB


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## funk_dynamite (May 13, 2012)

Not sure abotu using a chain catcher. Better to treat the cause not the symptom


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## supraholic (Oct 10, 2010)

funk_dynamite said:


> Not sure abotu using a chain catcher. Better to treat the cause not the symptom


I highly agree!!! If tuned right, chains shouldn't be dropping. Buying a chain catcher doesn't necessary fix the core of the problem. It's only a patch.

You'll see chain catchers on cross bikes because it's actually more functional in those environments than just road.


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## bikerjohn64 (Feb 9, 2012)

The other thing to have checked is to make sure that the chainline is correct.


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