Changed shifters and chain isn't in same spot My friend changed out the shifters on his bike and his rear derailleur isn't on the right sprocket based on what his shifter says. How can you fix this?
This happens everytime one replaces a component of the drivetrain since the original cable position is rarely restored.
He needs to do something called indexing the gears. It is a common procedure and there are many good tutorials online explaining how to do it much better than I could. Here is one I'd trust-