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Just installed a new GRX 1x11 groupset on my Diverge - first ride out today and it seems to be a little noisy. No grinding, but sounds like chain noise in the highest three gears. Chainline looks ok, and I've set the b-screw correctly. I'm using the GRX mech with XT cassette and chain.
Any ideas on what to look at? Thought it might be the cassette was loose but can't feel any play in it.
I've not added any additional chainlube, so could it be that?
Mine has never been happy in top three gears, fortunately they're bail outs so I can live with slightly crappy shifting and noise.
When you say you've set the B-screw correctly, how do you know? I can't recall Shimano being as prescriptive as SRAM in how far jockey wheel should be from cassette...
Mine is ok. Just fitted it with 42 front and 11-46 slx cassette on rear. Think it’s Shula I chain. Expected noise and shifting issues in bigger cogs but it’s great so far.
Chain length?
Sorry, I think I've got my terminology wrong here, when I mean the three highest gears - I mean the smallest cogs.
Nevermind, I misread the first post.
Sorry, I think I’ve got my terminology wrong here, when I mean the three highest gears – I mean the smallest cogs.
Nah, your terminology is right, but it's normally the low (large) gears that are noisy so I think people assumed.
Is the chain catching on the next biggest sprocket?
Is the chain catching on the next biggest sprocket?
No I don't think so, everything shifts really cleanly and nice (much better than my previous 105 groupset). There's just an odd pinging noise. Maybe it just needs to bed in a bit.
Don't think it is this but recently fitted Xt 11-42 cassette in GRX 1x11 set up and the noise was due to the cassette being loose. Why? Because, despite being an 11 speed cassette, it needed a spacer on the freehub to ensure it was clamped correctly. Taking a further look, I think it's because the inboard surface of the cassette is concave, making the clamp length more like a 10 speed cassette.
Because, despite being an 11 speed cassette
You're right MTB 11 speed cassettes have different (10 speed) spacing than road 11 speed cassettes, so need the spacer. In fact the non-series ultegra HG700 "road" cassette also needs a spacer.
I’d be checking:
Is the cassette compatible?
Does clutch on/off make any difference?
Mines still a bit noisy in the easier gears (11-42t cassette), don't really notice anymore. XT 11 speed cassettes are compatible as far as I'm aware and is what came with mine.
Looked at this a bit more last night ... seems to be when in the highest gear (smallest cog) the chain is catching the next cog just slightly because of the chainline, and the angle in which the chain goes towards the chainring.
I'm guessing I could add a drive side spacer to the bottom bracket to move the crank out slightly - but this might be at the expense of a worse chainline for low gears (biggest cogs).
prezet - this has been my exact experience with a 12 speed AXS mullet groupset on my road and gravel bikes. 10/52t cassette on a 40t chainring. The angle of the chainline and the close spacing of the smallest cogs means that the chain slightly catches on the adjacent cog at that end of the cassette.
The shorter chainstays on a road/gravel bike vs a mountain bike mean that the chainline at the upper and lower limits of the cassette is more extreme as the number of cogs increases and the space in between naturally becomes tighter. Spacing the chainset will always be a compromise at either end of the cassette.
Plus if you space out the drive side, with modern cranks the axle length is fixed. Therefore the non-driveside crank gets correspondingly closer to the chainstay. It's a compromise any way you look at it. Best you can do is reach a happy medium and live with a bit of noise at either extreme of the cassette.