Chain coming off lower jockey wheel

[jnatera]

I seem to be having a problem with my chain coming off the lower jockey wheel? The chain goes between the jockey wheel and the cage whilst I am still peddling. Only happens when in the small chainring on front and small ring on cassette.

I only replaced the chain a week ago due to my gears slipping. I did not have this problem with the old chain.

Your help would be appreciated.

 

[Puppet Master]

How old was the drive train when you changed the chain? if the chain was already very worn then a new chain is going to slip anyway. You shouldn't use small chainring and small spocket together, there isn't enough tension on the chain, so it will suffer from chainsuck. hope this helps.

 

[cobba]

Only happens when in the small chainring on front and small ring on cassette.

That's called 'Cross Chaining'.
Your new chain is coming off because it doesn't like being bent sideways as much as it does in the small / small gear combination.
Basically you shouldn't be using those gear combinations, they are noisy and they will wear out the chain, chainrings, cassette gears & derailleurs much quicker then what a straighter chainline will.

Using the big chainring & big gear on the cassette is also cross chaining and shouldn't be used.

A different gear combination using the middle chainring and a larger gear or a smaller gear on the cassette will give a similar or the same gear ratio as the small/small and big/big gear combination.

Gear Calculator: http://sheldonbrown.com/gears/




[video=youtube;yDPc1WqT2PE]http://www.youtube.com/watch?v=yDPc1WqT2PE[/video]

 

[T-Rex]

Only happens when in the small chainring on front and small ring on cassette..

There's your problem right there.

Easy fixed. Don't do that - as explained above.

To be a bit more clear, generally speaking you should only use your 3 - 4 biggest cogs on your cassette when you are in your smallest (granny) front ring, and your 3 -4 smallest cassette cogs when in your big front ring. Your middle ring should be OK for all the cogs on your cassette.

 

[Dales Cannon]

The reason the old chain didn't slip is that it was so worn it didn't have a problem bending sideways. As everyone else has said avoid at least 2 preferably 3 gears each side with the opposite chain ring, middle chainring is good for all the gears on the cassette. The question needs to be asked though if the chain was that badly worn what are the gears like? Putting a new chain on worn gears will mean the chain will wear out quite quickly.

 

[wattieez]

Also check the jockey wheel is in correctly, my old xt derauler did this and i had to pull the jockey wheel out and also all the little bits inside, put it back together and it was all good!