Loud grinding sound from DuraAce 7900 cassette

Discuss light weight issues concerning road bikes & parts.
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Anders
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by Anders

I have had an issue with a grinding sound from my DuraAce 7900 12-25 cassette. It gets very loud especiallly under heavy load on steep hills using the bigger cogs on the cassette or when sprinting. Changing the cassette to a Shimano 105 12-25 from my commuter the sound disapeared completely. Does anyone have any explanation to this? Is the 7900 cassette so soft that it wraps under heavy load leading to a misallignment between the sprockets and the chain? I also use the 7900 chain. Thinking if I should try a SRAM red cassette to get the low weight as 105 is a pig.

bm0p700f
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by bm0p700f

Sond like the cassette may be wearing or a worn chain. Some of the sprockets are Titanium (the larger ones) and it is the ones you would be using when climbing.

A new DA cassette and chain will no dount sort this.

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Anders
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by Anders

Cassette and chain are new. Done only about 300 km.

borja
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by borja

Can you confirm that the chain is placed correctly so it is not reversed? The text on the chain should be visible from the deraileur side of the bike

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Anders
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by Anders

Yes it is rotating in the right direction.

borja
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by borja

cassette is new and tightened, chain is new and placed correctly.. shifting is ok.. I have no idea. Maybe one of the pins which hold together the Ti cogs is loose? Can you check with your fingers each cog if there is any play or if there is any noise coming out?

Geoff
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by Geoff

Have you checked to confirm the correct lockring?

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Anders
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by Anders

Problem solved. The lockring was simply not tight enough. On my 105 I use an old XTR lockring and the thin washer have seen some cassettes and is therefore shaped. On the new Dura Ace it's flat and needs to be shaped for the lockring to seat properly. That requires some more torque than I expected.

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