Chain line problem

[Alison]

When the rear derailleur is set to the largest cog and the front is set to the largest chainwheel, back peddling causes the teeth to slip down the side of the chain at the bottom of the front chainring, knocking it off. The chain, it appears, is being pulled off the chainring as it is being pulled to far to the right when on the largest chainring for it to stay put.

I hope that makes sense

Is this curable. I'm using a 107mm BB and it's an 8-speed set up and the rear derailleur does seem to run through the gears OK.

Thanks

Alison

 

[Tallpaul]

Is this curable.

Don't back peddle?

Seriously though, you shouldn't ever really be in big-big or small-small.

Presumably if the chain is getting pulled to the right, a longer BB axle would cure it.

I run a 113mm axle on all my 8sp Shimano setups with no problems.

 

[P20]

Although it is possible to use that gear, its not ideal. It will accelerate wear on the drivetrain. Most bikes would probably do the same. As said its not advisable to use big/big or small/small