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?

Yes, worn drivetrains are noisier. Lubrication also affects noise.

Besides actual noise, hearing it depends on other factors, including background noise level, wind, wheel or frame resonance, echoing, etc

My road bike is very quiet with tire noise louder than the drive train. Except on roads with concrete "Jersey" barriers which seem to send chain noise directly to my ears

There's a climb I make in Tucson fairly regularly, the Catalina Highway on Mt Lemmon. When I get on the upper stretches of the road, up in the quiet pines, and I hit a certain level of fatigue after hours of climbing, I can suddenly hear nothing but chain noise. "Auditory hallucination" is the best term I have for it. Then it's time for a break.

On normal days, if I start hearing excessive chain noise after checking and maintaining things, that's my clue I'm wearing out a chain ring.

Most of my "auditory hallucinations" come the other direction. Climbing up hills on quiet roads, there's often a bird chirping in rhythm with my pedaling. Dead giveaway is when I get off the bike to check my pedals, or tires, or derailer, and the chirping stops.

Of course, the really evil birds fly off when I hit the brakes.

If many of my customers claims were correct the noise starting after a number of miles is because the bike got warmed up, really this has been claimed by many over my years of shop work. I wonder if it's more because the rider is getting tired and more ragged in their form. Andy

Most of my "auditory hallucinations" come from a cycling high.

It sounds like Olympic commentators on the air.

Perhaps I may need to seek professional help.

I should have mentioned I am hoping being able to hear relatively early drivetrain wear indicates I am moving from Padawan to Jedi biker status. Nowhere near master Jedi though.

I had a bottom bracket that would tick during the first 1/2 mile or so. Then it would go away. I was told to move 1/2 mile from where I was living.