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Strange noise coming from the rear of the drivetrain

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musiclover

New Rider
Hub Hero
Hi,

Could you help me understand this noise please?

It comes from the cassette or rear derailleur. I can tell the rear derailleur is adjusted properly. The rear derailleur plate looks a bit rounded but I think this is how Shimano 8150 rear derailleurs come. Nothing seems to be too unusual, and yet this annoying noise.
 
Hi,

Could you help me understand this noise please?

It comes from the cassette or rear derailleur. I can tell the rear derailleur is adjusted properly. The rear derailleur plate looks a bit rounded but I think this is how Shimano 8150 rear derailleurs come. Nothing seems to be too unusual, and yet this annoying noise.

I'm not sure. Could be just the chain (needs harder lube or similar), but it could be some adjustment.

What has changed since the drivetrain made no noise?

Does the sound happen only when pedalling?
 
Well it is a brand new build. The cassette and the chain were slightly used (only a couple of rides) on a previous bike where there was a different problem - slight grinding noise under load at the smaller chain ring which was only noticable when riding but not in the stand.
This one is different in a sense that I can reproduce it on a stand but do not really notice it a lot when riding. The system is a 12 Speed Shimano Ultegra road. Chain is a Shimano chain as well, lubricated by a Molten Speed Wax, chain was properly dergreased prior to that.
 
Well it is a brand new build. The cassette and the chain were slightly used (only a couple of rides) on a previous bike where there was a different problem - slight grinding noise under load at the smaller chain ring which was only noticable when riding but not in the stand.
This one is different in a sense that I can reproduce it on a stand but do not really notice it a lot when riding. The system is a 12 Speed Shimano Ultegra road. Chain is a Shimano chain as well, lubricated by a Molten Speed Wax, chain was properly dergreased prior to that.

Hmm. That's hard to tell without looking at the bike. I wrote a general guide article about the noise (how to figure out the source): Bicycle makes strange sounds

It's very tricky when a sound doesn't appear on the stand, only when riding. If it appears on the stand, it is usually easier to figure out where exactly it comes from.
 

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