I once replaced an overly stretched chain without replacing the cassette. Just trying to get by. There was no slipping or skipping but the drivetrain was really noisy. I felt that I could hear every roller "snapping" off the cog tooth. It was cured by a new cassette. I have no doubt that the noise was the mismatch of new chain and worn cogs.


At the end of this year's outdoor season the 9 speed drivetrain of one of my main bikes seemed a little noisier. Not a great deal but certainly slightly noisier. When I checked the chain it was stretched about 1/16" on a 12 inch rule. This winter I have a different bike on a trainer. Last week the 9 speed drivetrain seemed slightly louder. This bike has friction shifters and I could not trim the noise out. When checked, the chain was about 1/16" stretched on a 12" rule. Is this my imagination? Coincidence? Or is this the chain no longer meshing perfectly with the cogs? Perhaps before the cog teeth are are too worn? The change is slight but I feel it is definite. Has anyone else experienced this?