Hi guys, help required.
Symptoms... on granny ring the chain runs great down to the 14 tooth ring on the rear no probs there.
on the big ring the chain runs great up to the 30 tooth ring no probs there.
Alas on the middle ring it keeps jerking through the bottom jockey wheel,as if the jockey wheel is sticking, which it obviously isn't because it runs great on everything else.
Any ideas?