Chain dropping off - adjustment or just bad changing?

[MattDB]

I've got an 18sp bike and my chain drops comes off when I change down to the smaller front chain ring. This has only started happening recently and it's most often if I'm in the largest sprocket on the rear cassette i.e. I'm shifting from 10 --> 1.

So my question is, is this likely to be my gears badly set up or is this always likely to happen when shifting down like this?

 

[Milkfloat]

Well you were cross chaining before (which is not ideal). But a tweak of the lower limit screw on the front derailleur should stop the chain coming off.

 

[13 rider]

Search for dog fang chain catcher cheap remedy ,prevents chain coming off.

 

[Racing roadkill]

Search for dog fang chain catcher cheap remedy ,prevents chain coming off.

No it doesn't, it catches it when it falls off.

 

[Globalti]

It just seems to be a problem on some bikes, my old Roubaix used to do it, which caused some embarrassing offs at the foot of climbs when I was a road novice. I cured it by fitting a K-Edge chain catcher and have always had one on my bike since.

(Deda Dog Fang works well and is cheap but I don't think it works on anything other than a round tube.)

 

[mjr]

I agree with @Milkfloat - it sounds like the low limit is set too low. It's probably only slight, which would make it happen more often in the leftmost rear sprockets.

 

[fossyant]

Dog fangs are round tube only. They work well though

 

[youngoldbloke]

No it doesn't, it catches it when it falls off.

Depends where/how you fit it. One of my bikes with Veloce was prone to this. The Dog fang cured it

 

[mrandmrspoves]

Careful adjustment of the L screw on the front mech should stop the chain dropping over. Not cross chaining would be a good idea too. Chain catchers are probably a very good idea on a carbon framed bike - but nothing more than correct adjustment and maintenance (keep the derailleur and cables clean and oil the pivots) will cure most chain derail issues.

 

[MattDB]

Thanks everyone - had never heard of a chain catcher - it's not a carbon frame so I'll get adjusting and watch my changing

 

[13 rider]

http://www.halfords.com/cycling/bik.../deda-elementi-dog-fangdeda-elementi-dog-fang
Just a link to look at cheap way to prevent chain getting wedged into frame

 

[boydj]

Plan ahead. Change to the small chainring well before you get to the biggest cog.

And a dog fang does work well if fitted properly.

 

[MattDB]

Cheers both - it doesn't get wedged - just obviously the inconvenience of having to stop and put back on, then finding something to wipe oily hands on.

Bizarrely I was trying to help a broken-down cyclist last week who had a triple and the chain had got stick between two chainrings - it had actually gouged out a path in and there was no way it was coming out again. This had apparently happened when their light fell off and dropped onto the drive train.

 

[Globalti]

When I had my own problems with the chain dropping off on the down change, no adjustment seemed to prevent it so I came to believe it was caused by the derailleur flinging the chain across too violently. It certainly went over with a loud "clack".

Here's a K-Edge fitted to my bike, which had a band-on derailleur. The model for a bike with a bracket-mounted derailleur is far neater. It's a very well made little device.

 

[MattDB]

Thanks for that pic that's a nifty looking device!