# Noisy Ultegra Di2 rear mech



## part_robot (Aug 4, 2014)

Hi all, I hope you can help.

My Ultegra Di2 is noisy when pedalling... Kinda sounds like some old 1800s factory machine. It seems to be something related to the interface between the chain and the jockey wheels or the chain and the cassette... Perhaps the chain itself vibrating - I just can't tell. The hanger isn't bent and the alignment is spot on if I understand what I'm seeing correctly. The gears change fine and the chain is new (although the bike itself has done about 7500km). The only negative thing to note about the gears is that the chain will come off sometimes when I push the bike backwards in some combinations. The noise is much louder in the big ring than the small.

Here's a video of the noise https://www.dropbox.com/s/ekkm2tjjyfbizfz/VID_20160811_190854312.mp4?dl=0 The video makes it out to be alot louder than it really is, but it's still pretty annoying.

Any ideas? All help gratefully received as always.


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## Migen21 (Oct 28, 2014)

Tell me about your chain? What model? How is it installed? What kind of lube?

Edit: Also, a video from the rear, lined up with the chain line, with perhaps some shifting activity (up and down the cassette) would be helpful as well.


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## MMsRepBike (Apr 1, 2014)

I would just bring the bike into a shop if I were you. I'd ask them to put the derailleurs back to zero, remove all trimming in the etube software and make sure they're as they were when new. Back out the limit screws, support bolt, everything like it was new.

Then do it right from there.


Have you tried adjusting the rear mech while in adjustment mode? The one where you hold the button and turn the light red and turn the shifters into a barrel adjuster? It could be something that simple but who knows.

Also how well is the b-tension adjusted? Is that spot on?

Oh, and I'm not clicking your link so can you tell me what generation we're talking about here?


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## Migen21 (Oct 28, 2014)

I watched the video (the link is to an MP4 video on his drobox). The derailleur appears to be an Ultegra 6870.


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## part_robot (Aug 4, 2014)

Migen21 said:


> Tell me about your chain? What model? How is it installed? What kind of lube?
> 
> Edit: Also, a video from the rear, lined up with the chain line, with perhaps some shifting activity (up and down the cassette) would be helpful as well.


KMC X11-SL Silver 11 Speed Chain. I use Lifeline PTFE chain lube. The chain is the same length is the one that came with the bike, and has a power link or whatever KMC call it. Prior to chaining the chain it was also noisy so I don't think it's that.

Video from the back: https://www.dropbox.com/s/v5gksz7mqv59ba4/VID_20160811_202829997.mp4?dl=0


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## part_robot (Aug 4, 2014)

MMsRepBike said:


> I would just bring the bike into a shop if I were you. I'd ask them to put the derailleurs back to zero, remove all trimming in the etube software and make sure they're as they were when new. Back out the limit screws, support bolt, everything like it was new.
> 
> Then do it right from there.
> 
> ...


Adjustment mode was the first thing I tried. No dice.

What do you mean by b-tension in the case of Di2?


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## part_robot (Aug 4, 2014)

(Ahah... I discovered the Di2 manual online. I'm going to have a poke with the setup instructions there too)


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## part_robot (Aug 4, 2014)

Ok, done the stuff in the manual related to b screw and adjustment mode. No difference. The b screw didn't appear to do anything for what it's worth


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## MMsRepBike (Apr 1, 2014)

How do you know the hanger is not bent?


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## part_robot (Aug 4, 2014)

MMsRepBike said:


> How do you know the hanger is not bent?


Short of getting a new one or one of those fancy tools, I'm not 100% sure. However, looking at it as well as using a ruler suggests if it is out of line it's not by very much at all.


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## Migen21 (Oct 28, 2014)

I can't see what chain ring you are in in front, and I don't know if it's where your noise is coming from, but your chain looks too short to me.

take a look at this article and check yours
Chain Length Sizing | Park Tool

And you really can't eyeball the hangar alignment. It's a very subtle thing, and doesn't take much to have an effect.


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## goodboyr (Apr 19, 2006)

The only way to check hanger alignment is with a hanger alignment tool. 

Sent from my SM-G900W8 using Tapatalk


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## part_robot (Aug 4, 2014)

Migen21 said:


> I can't see what chain ring you are in in front, and I don't know if it's where your noise is coming from, but your chain looks too short to me.
> 
> take a look at this article and check yours
> Chain Length Sizing | Park Tool
> ...


Big chainring. Doesn't the fast and easy changing of gears suggest it's not the hanger? Wouldn't I see symptoms other than noise?

Out of curiosity, why isn't the effect of a bent hanger solved by adjusting the position of the derailleur in adjustment mode?

I'll have a play with length tomorrow.


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## part_robot (Aug 4, 2014)

Migen21 said:


> I can't see what chain ring you are in in front, and I don't know if it's where your noise is coming from, but your chain looks too short to me.


I just checked out the chain according to the Park Tool site and the length is fine. In big-big there is an S-bend in the chain around the pulleys. In any case, this happens throughout the entire range of all gears (but worse with the big chainring).


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## fronesis (Jan 22, 2014)

Here's a thought from left field – are you sure it's a problem and not just a bit of new chain noise? 

I just set up my first Di2 (6870) bike this summer, and it's simply got more chain noise than any other bike I've had before or currently, which includes Campy Record, Chorus, Athena, and Shimano 105 5800. 

I started with a straight hanger; I know, because I straightened it. And both FD and RD are set up pefectly and have been flawless for over 1000 miles – literally zero missed shifts and no derailleur noise. But the Shimano 701 chain on the 6870 jockey wheels and ultegra cassette simply makes more noise. For me the "solution" was to go back to Chain L lube, which quieted it down significantly. But my 105 out of the box was quieter than the 6870.

I sort of assumed it had something to do with the way the Di2 system worked (with the overshifts). In my case I'm sure it's only chain noise, and not a problem. And listening to both your videos, yours seems to sound about like mine.

I don't think it would hurt to try a thicker chain lube and see how it sounds. You could also try a different chain.

EDIT: if you do a google for noisy di2, you'll get a lot of threads that start like yours. I found this one useful as SO many people here basically say "yep, my Di2 is a bit noisier than other groups I've had" Chain noise on a new Ultegra Di2 bike. - BikeRadar Forum


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## part_robot (Aug 4, 2014)

fronesis said:


> I don't think it would hurt to try a thicker chain lube and see how it sounds. You could also try a different chain.
> 
> EDIT: if you do a google for noisy di2, you'll get a lot of threads that start like yours. I found this one useful as SO many people here basically say "yep, my Di2 is a bit noisier than other groups I've had" Chain noise on a new Ultegra Di2 bike. - BikeRadar Forum


Awesome, thanks.

It's definitely a loud groupset that's for sure... it's comforting to hear other people are having the same issue and it's not just me going crazy.

I can't help but feel it might be chain noise also - and, in particular, that dry lube. I lube the bike once a week (I typically do 150-250km) but it always kinda feels like the chain is too dry. I have a vague recollection that when I changed the chain and kept the factory lube for a couple of runs it was quieter than it is now. Might have a look in that direction this weekend.


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## part_robot (Aug 4, 2014)

I think what I'm going to do next is drench the chain in lube. I only have the PTFE one at hand but I'm going to give it a series of treatments with long waits between and possibly some hairdryer action. See if I can build a good layer up.

If that fails to do the job, I might switch to a Dura ace chain as I'm reading in a couple of places now that those unidirectional ones might vibrate less... Same price as the KMC, fortunately.


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## Srode (Aug 19, 2012)

I just went out and compared my mechanical 6800 to Di2 bike for noise and the mechanical set up is noisier, both set up spot on for trim. The Di2 is on an alumimum framed bike with aluminum rims not very deep, and the mechanical is on a carbon frame with deeper carbon rims, so I'm guessing some of my difference is the wheels / frame which can amplify noise.


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## MMsRepBike (Apr 1, 2014)

part_robot said:


> I think what I'm going to do next is



What you should do next is bring your bike into a bike mechanic. Have them align your rear hanger. Have them setup the Di2 properly.


My Di2 setup is the quietest and smoothest thing you could possibly imagine. And it's on a Rotor crankset. Those cranks are supposed to be noisy and the groupset is supposed to be noisy... guess what? Neither are, it's just people who don't have a clue how to fix a bike trying to fix a bike and giving up. I can promise you that Di2 setups are NOT more noisy than mechanical.

Take the bike to a professional.


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## wim (Feb 28, 2005)

Because you keep mentioning vibration (and I can see it in your video clip), it might be helpful to bring up so-called chordal action here. All chain drives are afflicted with this, including the noise that comes with it. The vibration from chordal action is so reliable that it can actually be used to read power. Someone made a power meter that did just that. Not sure if it's still made or sold. 

2.2.1 Chordal Action

Looking at your video, I wonder if you're concerned mostly by the noise coming from an upside-down bike. That could be a bit misleading. For example, the weight of the chain exerts some degree of downward force on the lower derailleur pulley with the bike upside down. With the bike right-side up, the weight of the slack lower-run chain pulls it away from the lower pulley. That could make a real difference in what you hear.

The chain coming off when you push the bike backwards means nothing. It doesn't take much for a chain to come off a sprocket. For example, if you lean a bike over 20 degrees or so and pedal backwards, the chain often derails just by its own weight to the next smaller sprocket even on a perfectly adjusted and aligned drivetrain.


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## Migen21 (Oct 28, 2014)

I'm with MMsRepBike here.

Take it to a shop.

Di2 6870 RD's are not inherently noisy (far from it). Mine is the quietest thing you can possibly imagine. I'm running it on two different bikes. One carbon and one Ti. They both run dead silent, even on the large chainring.

Something is wrong. Alignment, adjustment, chainline, etc... take it to a good shop and have them assess it.

BTW, I don't know anything about KMC chains, or the lube you are using, but putting a new Shimano 11sp chain on might help. They come pre-lubed, and will last you a good long time.


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## wim (Feb 28, 2005)

Migen21 said:


> Take it to a shop.


Second that. But don't be too surprised if they find (or hear) nothing out of the ordinary.

If you decide to solve this by yourself, hang or stand the bike right-side up. On modern derailleur bikes, you simply can't diagnose a vexing drive train issue with the bike upside down.


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## part_robot (Aug 4, 2014)

It's similarly noisy the right way up, by the way, but I'll definitely take that into consideration in future. Plus it's a good excuse to buy a stand 

I've saturated it in several loads of PTFE lube and whilst that may have softened the sound a bit, it's still noisy. So next up: try a dura ace chain

By the way do I have to use a hanger aligner or can I just get a new hanger? The hangers are only £15 for my bike...


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## goodboyr (Apr 19, 2006)

You MUST use a hanger alignment tool. Merely bolting on a new one does not ensure alignment. Neither does eyeballing it. And you cant adjust out a misalignment via the micro adjust. Misalignment makes the derailleur path not parallel to the cogs as it moves along the shift path. So an adjustment at one end will be out by the other end. 

Sent from my SM-G900W8 using Tapatalk


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## part_robot (Aug 4, 2014)

Perfect, thanks.

This forum is awesome - I really appreciate the help.


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## goodboyr (Apr 19, 2006)

And we did it all without cx's help!

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## part_robot (Aug 4, 2014)

Ok, I just rigged up a couple of tools to check the alignment. One references the small face of the hanger, and one threads into the hanger. Both show a total different from the 12pm to 6pm position of about 5mm... I.e. +2.5mm one way and -2.5mm the other. 3pm to 9pm is bang on. This amounts to a 0.1 degrees.. can that really make a difference? That's less that the tolerance of most of the alignment tools.

So what we know so far
1/ For me, the hanger alignment is ok based on the above
2/ The chain length is correct
3/ The chain is well-lubricated with PTFE lube - is PTFE the issue here?
4/ The gears shift fast and perfect every time
5/ The chain doesn't rub - e.g. on the sprockets
6/ The chain is pretty new

Additionally (not mentioned) the cassette is in excellent condition.

So the only things I can think it can be is
1/ My bike doesn't like the KMC chain for some reason?
2/ The jockey wheels are at fault somehow?

Any ideas? I'm running out. Don't really want to take it to a shop just yet although I may eventually.


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## goodboyr (Apr 19, 2006)

Deleted.

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## Migen21 (Oct 28, 2014)

Forget about Dura Ace chains. Just get the XT/Ultegra version (whatever it's called now). They are excellent chains, and much cheaper than Dura-Ace.


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## part_robot (Aug 4, 2014)

Update: replacing the KMC chain with a brand new Dura Ace one has noticeably reduced the noise. Not totally, mind, but it's almost silent in the small chain ring throughout the range and pretty quiet the smallest 3 or 4 gears in the big chain ring. Big-big and thereabouts is noisy as you might expect given the bending required of the chain.

As a bonus the chain was on offer and almost the same price as the Ultegra.


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## wim (Feb 28, 2005)

part_robot said:


> Any ideas? I'm running out. Don't really want to take it to a shop just yet although I may eventually.


Perhaps you're just overly sensitive to the normal and unavoidable vibration and noise of a chain drive (not just on bicycles, google "chordal action"). You can't expect a drive pulling rigid straight links around a radius to run as quietly as a drive using a bendable material like a belt.



> Big-big and thereabouts is noisy as you might expect given the bending required of the chain.


Not really. Big-big has the chain bend much less than small-small. The increased noise you're hearing is caused by increased tension in the chain.


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## part_robot (Aug 4, 2014)

Definitely makes sense regarding chain tension. I experienced this when sizing a chain for a vintage bike actually. Should have remembered


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## part_robot (Aug 4, 2014)

Update2: I've now used Fenwicks Stealth lube on the chain and it's even quieter. Barely audible when on the road in all but the largest 3 rear sprockets with the front big ring.


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## Scott-op (Jun 18, 2021)

goodboyr said:


> The only way to check hanger alignment is with a hanger alignment tool.
> 
> Sent from my SM-G900W8 using Tapatalk


The derailleur hanger can be checked for straightness / alignment using your own eyes to verify that the chain as it runs through the tension and jockey wheel pulleys is also parallel with the plane of the cassette sprocket. Yes, this is called " eyeballing it " but is a first check and can be done without the hassle of a Park alignment tool.


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