Where is the sound coming from?

[AgMar]

Hello everyone, this is another post about where is the sound coming from?!

Background: it's an Ultegra 11-30 cassette, Ultegra 11 speed chain, DA 9100 PM cranks on an Aethos, Enve 3.4's with DT Swiss 240 hub.

The sound is not a creak, or a whine, but more like a chain rubbing sound. The sound is low pitched. It doesn't happen out of the saddle, or big power efforts, or climbing, or coasting / freewheeling. It only happens around the lower gears, with the chain on the big ring, when spinning normally and gently, almost on every revolution of the crank, there'll be the sound, so it's not a constant sound when peddling.

I've cleaned the freehub, re greased, removed the cassette and reinstalled, cleaned the chain, tried loosening the jockey wheels, checked that the chain isn't rubbing against the FD, but there's still that weird sound.

Does anyone have any ideas or come across something like that on their bikes?

Thanks

[Karvalo]

If it sounds like chain rub it's probably chain rub. You say you've checked it's not rubbing the FD but have you accounted for flex? Otherwise it could simply be the chain rumbling on the rings and cogs. 9100/8000 just runs louder than previous gen Shimano.

[kode54]

Check chainring bolts. Could flex if one is not torqued properly or loose. Use anti-seize when reassembling.

[AgMar]

It's really difficult to explain the sound, as it's not a creak or a whine, but the best I can come up with is it sounds like metal on metal. It doesn't make the noise under load, so flex wise not sure. Will check the chain ring bolts which is something I have not checked so far. Trying to isolate where it's coming from, it seems like it's the cassette / RD / jockey wheels, which is why I have so far focused on those areas.

[kode54]

Chain too long?

[coffeeaddict]

Just to be clear, the sound only shows up when in the large chainring and the lower (I.e. higher tooth count) rear cassette gears? If so that's probably down to the poor chain line and possibly the indexing being slightly out.

[kode54]

Big big? Di2?

Then use the chainring trim function.

[gorkypl]

+1 for the new generation being loud on higher gears. Changing lube helps a bit.

[AgMar]

The sound is when it's big ring / big cogs, usually around the 6th - 11th cogs. Di2. Chain line is not an issue I think. I use Squirt and it makes the drivetrain almost silent, apart from this weird intermittant sound, in specific circumstances. Thanks for all suggestions. Will relube and check chain rub, plus the chain ring bolts

[TobinHatesYou]

Record a video clip of the sound if possible.

[smokva]

Usually you can hear "metal sound" if you are cross-chaining big-big. With 11 speed setup last 3 big cogs will sound different. If it's on the last 6 cogs as you have said (usually around the 6th - 11th cogs) something else is not setup properly. Check chainline, chain wear, FD cage rub, hight of pulleys, chain length...

[TobinHatesYou]

Just spitting out a few possibilities…

B-screw adjustment?
Chain routed under instead of over the pin that braces RD cage?

[basilic]

I once had a sound like this (big-big) from the chain rubbing the underside of the fd cage (not the sides); the fd had slipped down somehow.

[TobinHatesYou]

I once had a sound like this (big-big) from the chain rubbing the underside of the fd cage (not the sides); the fd had slipped down somehow.

Oh right, that's another sneaky one. Sometimes the top of an FD cage has a little nub on the inside face that guides the chain during upshifts.

[Kingstonian]

Have you found the source of the sound yet?