Originally Posted by
Frum
I recently upgraded my bike from a triple to a double without changing the bottom bracket, which was sized for a triple.
Now, if I am in the largest cog in the back and in the front, when I pedal backward the chain will actually shift down from the top.
I'm guessing that isn't normal and my bottom bracket is too wide. The drive train is completely silent when pushing forward, however.
Do I need to change my bottom bracket?
One of my bikes will do that. It is 53/39 front and 9x/34/11 rear. I just avoid pedalling backwards in the 53/34 combination. That 53/34 combination is cross-chained and, in theory, should be avoided anyway. The problem is worse if the bike has a short wheelbase. On my bike, there isn't room to bring the crankset in. I suspect you should just learn to live with this and avoid the situation that derails the chain. how is chain alignment in more appropriate combinations?
Don in Austion