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Any tips for tracking down squeaks? Very high pitched chirruping coming from somewhere when using big chainring combined with bigger half of cassette (bigger sprockets). Completely silent for big chainring with smaller sprockets and also small chainring all the way across the cassette.

Thank you

17 comments

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Spangly Shiny [247 posts] 1 month ago
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First check for chain rub on the front derailleur. If it isn't that invest in one of these:

https://www.ebay.co.uk/p/Auto-Mechanics-Stethoscope-Car-Engine-Block-Dia...

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Podc [131 posts] 1 month ago
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Check chainring bolts are nice and tight.

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rdmp2 [70 posts] 4 weeks ago
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Thanks both- good suggestions. Definitely not fd rubbing on chain. Chainring bolts are as tight as I can get them (recommended torque?) but can’t rule that out. Fact it’s only in certain gear combos (and fine in small chainring) makes less likely? Worth cleaning and retorquing bolts?

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hawkinspeter [3481 posts] 4 weeks ago
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That the noise only happens with big/big cogs, then I'd be thinking about chain tension and rear derailleur (as the front derailleur has already been checked). Is the chain long enough and are the jockey wheels in need of replacement?

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ktache [1488 posts] 4 weeks ago
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Remove seatpost, clean it, the tube and the fastener, lube everything and put it back together.

This has stopped what I had always assumed was a creak in the bb or chainset.

And it's never a bad idea, chatting to a bloke unlocking an Orange mtb ouside the supermarket the other day, lovely bike, there was such disappointment in his voice about the seatpost cold welding itself into the frame.  LBS could do nothing.  It reminded me, and I will be doing this to my everyday bike this long weekend.

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hirsute [784 posts] 4 weeks ago
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Take off and nuke it from orbit - it's the only way to be sure.

Rear derailleur sounds a good bet.

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TheLonelyOne [387 posts] 4 weeks ago
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You're describing a cross-chaining scenario. I had a similar effect after I'd cleaned a cassette - totally stripped it of all oil and residue - and it was the inner plates of the chain rubbing against the cassette teeth as the angle of the chain increased. A temporary squirt of WD40 on the cassette silenced it, and then giving the chain a (probably excessive) coat of lube fixed it for good.

 

 

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rdmp2 [70 posts] 4 weeks ago
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Thanks all. Hard to track down as completely silent in workstand.

Hawkinspeter- Chain definitely right length. Jockey wheels done 4000 miles and still look fine.

Ktache- Will re-grease seatpost but is that likely given that it depends on what gear is selected?

Hirsute- what do you mean? Incorrectly adjusted? Rubbing?

Lonelyone- definitely seems to be related to angle of chain. I tend to be quite sparing with lube so will see if liberal application does anything.

 

 

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hirsute [784 posts] 4 weeks ago
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If it is fine on the smaller chain wheel across all sprockets, then not sure the angle is the issue.
Big to big might be worth checking the position of the rear cage.

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madcarew [1003 posts] 4 weeks ago
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If it's a high pitched squealing/ chirruping I'd be going for jockey wheels. Chain under extra tension/ particular angle causing rubbing on some part (perhaps the squared washers they fit in?). To eliminate it I'd try a spray of wd40 around the jockeys and their bushes.

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generationally [2 posts] 4 weeks ago
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Sounds pretty similar to what I have experienced - I can especially relate to this "chirruping" sound.

I took my jockey wheels off and they had pretty much gunk stuck to the sides of the wheels. Since the top jockey wheel needs to be able to move sideways (on shimano at least) then I believe the stuck gunk prevented that movement from happening freely. Whether this caused the sounds or they were just worn out, I don't know. 

Instead of cleaning the wheels, I just replaced them as they had already seen some 12000km. The chirruping sound has been gone since.

Your issue might be different but I thought that I would share my experience anyway.

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khaostik [7 posts] 4 weeks ago
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If by chance you have chainstays with 405mm lenght not every chain brand will work OK.

I have a giant tcr advanced sl and a grinding noise appeared as described when I replaced the original kmc chain by a shimano chain. I've then putted a kmc chain again and the noise went away.

 

Cheers,

 

Filipe Dias

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rdmp2 [70 posts] 4 weeks ago
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Thanks again.  New jockey wheels ordered and will update after trying that (with wd40 application if no improvement). Hirsute- Will try to check position of rear cage but not 100% sure what I’m looking for! 

Khaostik- 407mm chainstay, kmc chain. When it wears out I’ll try a different brand

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ktache [1488 posts] 4 weeks ago
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Weird B-screw adjustment?

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AfterPeak [150 posts] 3 weeks ago
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Jockey wheels is my guess. I get this when they have got wet and washed oil out and then dry and they sqeill. The reason for I am guessing it happens with the gear combination is the faster chain travel (just a guess). Anyway I remove both jockey wheels clean them, relube and reinstall them and it sorts it. 

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rdmp2 [70 posts] 3 weeks ago
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If anyone interested- upper jockey wheel was culprit. Corroded around bushing & cover. Replaced and now beautifully silent

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hawkinspeter [3481 posts] 3 weeks ago
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rdmp2 wrote:

If anyone interested- upper jockey wheel was culprit. Corroded around bushing & cover. Replaced and now beautifully silent

Called it!