When you purchase a new chain, you want to match it with a new sprocket.
Why Do You Not Run A New Sprocket On An Old Chain?
If you install a new sprocket and running on used chain, your pitch is going to be offset. Pitch is the distance from one pin to the next pin; and that distance needs to match on both the sprocket and chain.
Why Do You Not Run A New Chain On A Used Sprocket?
If you run a new chain on a used sprocket, the chain will not have full engagement with the sprocket teeth; and it will try to jump off the sprocket. The contact area for the teeth on a worn sprocket will have a different pitch length than on a new sprocket. The result is it will not seat the chain correctly.
Sometimes t...