# Chain Noise Under Load



## mikiek (Aug 18, 2014)

OK - I'm hearing the chain rubbing the FD cage when I mash on the cranks. There's more than a few posts here regarding that. I realize I have an FD adjustment to do. 

But the more general question that I don't understand is why does this happen under load? Must be missing something because it seems to me that if I am mashing the cranks, the chain would be just as tight as it could be and not easily coming into contact with the cage.

Please set me straight...

BTW this is an Ultegra drive with maybe 1K miles on it.


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## ibericb (Oct 28, 2014)

The rubbing under load generally comes from flex that distorts the chain line, either from the chainring or from the frame between the BB and the rear axle, or most likely from a combination of both to some degree. It's not an uncommon problem. Here's one example from Lennard Zinn's Technical FAQ column (first question). You'll also find threads in the forums her reporting the same kind of problem, such as this one.


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## tlg (May 11, 2011)

Pat yourself on the back. You have massive power and are flexing the frame and/or wheel.


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## mikiek (Aug 18, 2014)

ibericb said:


> The rubbing under load generally comes from flex that distorts the chain line, either from the chainring or from the frame between the BB and the rear axle, or most likely from a combination of both to some degree. It's not an uncommon problem. Here's one example from Lennard Zinn's Technical FAQ column (first question). You'll also find threads in the forums her reporting the same kind of problem, such as this one.


ibericb - good information as usual. Thanks. Odd thing in my case is it's not the small rear cog, it starts happening on the 3 largest cog and continues on the larger 2. Biggest cog or smallest, I would expect some rub. This kinda surprised me especially since I had just made a serious effort to fine tune the FD.

Like the second link says - just stop mashing and the problem will likely go away. I realize mashing is not the best technique, but sometimes after a stressful day it is a great way to get it all out.


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## tlg (May 11, 2011)

mikiek said:


> Odd thing in my case is it's not the small rear cog, it starts happening on the 3 largest cog and continues on the larger 2.


Not odd at all. The farther up your large cogs, the more extreme the chainline gets. So it takes less flex to create rub.


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## mikiek (Aug 18, 2014)

tlg said:


> Not odd at all. The farther up your large cogs, the more extreme the chainline gets. So it takes less flex to create rub.


Good point.


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## Srode (Aug 19, 2012)

easy to get rid of if you trim the FDR when in those 3 cogs. Trim works fairly well on 6700 Ultegra and very well on 6800 Ultegra.


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## ibericb (Oct 28, 2014)

mikiek said:


> ibericb - good information as usual. Thanks. Odd thing in my case is it's not the small rear cog, it starts happening on the 3 largest cog and continues on the larger 2. Biggest cog or smallest, I would expect some rub. This kinda surprised me especially since I had just made a serious effort to fine tune the FD.
> 
> Like the second link says - just stop mashing and the problem will likely go away. I realize mashing is not the best technique, but sometimes after a stressful day it is a great way to get it all out.


Mashing vs. spinning means more force applied for the same power output. More force = more flex, wherever it's coming from. As tlg noted, it can also come from rear wheel flex that distorts the chain line by moving the cassette out of plane.

It may be with some fine tuning of the FD you can get it to go away. The 11-speed tolerances are pretty small, and 1mm makes a difference. If it's a 6800 set, it can take some fiddling. My LBS tried 3 times on my Domane when it was new last October, and it still wasn't right. I finally took maters into my own hand , and it's been fine since. It's one of those fiddly things. It turned out there was about a 1/2" of excess slack in the FD cable.

Since you ay it happens only under load I'm assuming you've tried eliminating the rub via the trim feature with the 6800 shifter/FD. If not, go back to school on that feature. It's a key to getting the FD in the optimum position.


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## mikiek (Aug 18, 2014)

ibericb said:


> Since you ay it happens only under load I'm assuming you've tried eliminating the rub via the trim feature with the 6800 shifter/FD. If not, go back to school on that feature. It's a key to getting the FD in the optimum position.


Yup, it is the 6800. The trim didn't help. Tonite I loosened everything up - cable, mounting bracket - and started at square one again. I did notice I had the low adjustment set wrong, it was too far out so I tweaked that back in. I can see where that might cause some chain chatter.

I was going by the Shimano specs, and found out that some of the adjustments are supposed to be made with the cage in the trim position. Have not done that before, always either low or high. It was too late to test ride so I'll check it out tomorrow.

One question, a little off topic - but hey it's my thread. While working this evening, I could barely see any movement of the cage when I go to the trim position. I mean you really would have to know it was supposed to move or else you would never have noticed anything. We're talking probably less than 0.5mm . Is that about right? Is that trim position even adjustable?


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## Srode (Aug 19, 2012)

The amount is not adjustable but you should have more than .5mm set up right. Mine look like around 1mm easily. Might want to go through the whole FDR set up from scratch (with the exception of height) to get it dialed in. The amount of cable tension to start has a big impact on how much trim you get if I remember correctly.


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## ibericb (Oct 28, 2014)

Srode said:


> The amount is not adjustable but you should have more than .5mm set up right. Mine look like around 1mm easily. Might want to go through the whole FDR set up from scratch (with the exception of height) to get it dialed in. The amount of cable tension to start has a big impact on how much trim you get if I remember correctly.


That sounds right to me. The initial cable tension is one of the keys. Do the fine adjustment of cable tension with the barrel adjuster with the chain crossed big-big. It can be fiddly, but once you get it right it's a thing of beauty.


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## mikiek (Aug 18, 2014)

ibericb said:


> That sounds right to me. The initial cable tension is one of the keys. Do the fine adjustment of cable tension with the barrel adjuster with the chain crossed big-big. It can be fiddly, but once you get it right it's a thing of beauty.


The FD is shifting nicely, particularly after I re aligned last night. It seems like something else is happening to make that chain move when it's loaded up.

Let me throw this into the conversation - one of those 'why the hell didn't he say that to start with' things. I didn't think it would have mattered. I was in a pretty bad wreck 2 weeks ago. The bike went down on the DS and then skidded into a curb. I went about 15 feet further. The RD hanger was bent so I replaced that - and I have the Park hanger alignment tool so I believe that is in line. About a week later I realized the RD cage was bent so I replaced the entire RD. The cranks don't have any sideways wiggle so I would think they and the BB are OK. The wheels checked out for radial and lateral true. Not sure what else might have been bunged up.


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## Srode (Aug 19, 2012)

So you still get the same result or it's fixed? Did you get more movement when trimming?


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## ibericb (Oct 28, 2014)

mikiek said:


> The FD is shifting nicely, particularly after I re aligned last night. It seems like something else is happening to make that chain move when it's loaded up.


So is it still rubbing when pedaling under load, or is that resolved?



> Let me throw this into the conversation - one of those 'why the hell didn't he say that to start with' things. I didn't think it would have mattered. I was in a pretty bad wreck 2 weeks ago. The bike went down on the DS and then skidded into a curb. I went about 15 feet further. The RD hanger was bent so I replaced that - and I have the Park hanger alignment tool so I believe that is in line. About a week later I realized the RD cage was bent so I replaced the entire RD. The cranks don't have any sideways wiggle so I would think they and the BB are OK. The wheels checked out for radial and lateral true. Not sure what else might have been bunged up.


Is this all new since the crash? What's the frame material? It happens only when on the large ring, and when crossed to one of the three largest rear cogs, getting worse with each step up in cog size?

If it happens only when pedaling under a significant load (i.e., not a problem in the same gear combination if spinning without a load, like on a workstand), then there's something flexing and moving in response to the load. It could be a number of things from frame movement (bottom bracket, chainstays, rear dropout, hanger, rear wheel, etc.) in response to your awesome power (had to get that in), or rear wheel flex, or pedal axle/chain ring movement. If it also happens when largely load free, then there's definitely an alignment issue. Of course it could be, and most likely is, just a tad off on alignment such that it's fine in the low load domain, and then normal flex makes it rub. 

If it were me, and it didn't run before the crash but does now, and I felt I had the derailleurs set up properly, and couldn't resolve it there, and I had eliminated all the alignment issues I could, I'd take it to a very competent mechanic, because at that point it's beyond my limited knowledge and experience.


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## mikiek (Aug 18, 2014)

I don't think it's fixed. I have to say 'think' because half the time I'm riding there is too much wind in this old war dog's ears and I can't hear anything else. But it kinda sounds like it is happening in more than the 3 big cogs.

I have a bud who will lend me his trainer and maybe then I can make a better assessment. I will have that tomorrow.

You know lining up that 6800 cage with the large chain ring is tough and a little confusing. The outer wall of the cage is not flat. From the rear to the front, the wall runs for about 1 1/2" then it indents and runs for another 1" . What part is supposed to be directly over the chain ring?


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## ibericb (Oct 28, 2014)

mikiek said:


> I have a bud who will lend me his trainer and maybe then I can make a better assessment. I will have that tomorrow.


If any of the alignment issue involves wheel or frame flex, it may be good on the trainer and still troublesome on the road.



> You know lining up that 6800 cage with the large chain ring is tough and a little confusing. The outer wall of the cage is not flat. From the rear to the front, the wall runs for about 1 1/2" then it indents and runs for another 1" . What part is supposed to be directly over the chain ring?


I focus on the section where the chain is closest to the FD cage and the chain ring, which for the outside is that lower forward indented portion.


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## mikiek (Aug 18, 2014)

Sorry it's taken a few days

Friday night I broke down the entire drive train front & rear. Took them completely off the bike and had everything laid out on the garage floor. I remounted and aligned the RD hanger, RD & FD . Everything looked good on the workstand but I did not get to ride.

Saturday I was setting up a new SMP saddle and the seat post collar stripped out so I couldn't ride. I did get the trainer.

Today, I got a new collar. Put the bike on the trainer and it sounded good. After the rain stopped I got some road time and again it all sounded good. Shifting was great also. So, fifth time the charm? Not sure what I did differently in the alignment, but must have done something.

So after all this I must chalk this one up to user error. Thanks for everyone's support!


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## ibericb (Oct 28, 2014)

Excellent.


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## johnlwarner (Mar 19, 2012)

*That's the rub?*

I remember looking at this thread 2 years ago. I'm going to have to try the FD adjustment, but here goes another version of what seems to be the same issue. No noise on trainer. 

Tarmac 2018 S-Works Frame, DA 9100 Mechanical Group Set 53/39 & 11-28T sprockets, with rebuilt wheel from 9000 rim brake free hub 36 spoke. When the bike was built new 2 years ago I noticed under high torque I would get some rear derailleur noise. It seems to be indexed correctly no noise and shifts crisply on the stand. This went away and I forgot about it. Then I just recently replaced all of the drive chain...rings, chain, cassette. I did the install myself and the chain is exact same length/link etc. Now the noise is back, it's on both rings and the lowest gears (the last larger 3-4 sprockets), mostly up hills under higher power although I can reproduce under heavy load on flats. One theory I want to put out there is that the dish of this wheel seems to be slightly offcenter...the bike shop did this, and I've not addressed it. I've read about bike frame flex and that could be some of it too but I'm hoping that is very minor component. Any other thoughts?


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## cxwrench (Nov 9, 2004)

johnlwarner said:


> I remember looking at this thread 2 years ago. I'm going to have to try the FD adjustment, but here goes another version of what seems to be the same issue. No noise on trainer.
> 
> Tarmac 2018 S-Works Frame, DA 9100 Mechanical Group Set 53/39 & 11-28T sprockets, with rebuilt wheel from 9000 rim brake free hub 36 spoke. When the bike was built new 2 years ago I noticed under high torque I would get some rear derailleur noise. It seems to be indexed correctly no noise and shifts crisply on the stand. This went away and I forgot about it. Then I just recently replaced all of the drive chain...rings, chain, cassette. I did the install myself and the chain is exact same length/link etc. Now the noise is back, it's on both rings and the lowest gears (the last larger 3-4 sprockets), mostly up hills under higher power although I can reproduce under heavy load on flats. One theory I want to put out there is that the dish of this wheel seems to be slightly offcenter...the bike shop did this, and I've not addressed it. I've read about bike frame flex and that could be some of it too but I'm hoping that is very minor component. Any other thoughts?


You used to get rear derailleur noise 'under torque'? Not possible. Under lots of power or not won't make a difference on the rear derailleur. Rim centering? Won't have any effect. Where are you getting noise now? Front derailleur? I see wayyyyy more toggle link derailleurs set up incorrectly than ones set up correctly.


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## Fredrico (Jun 15, 2002)

johnlwarner said:


> I remember looking at this thread 2 years ago. I'm going to have to try the FD adjustment, but here goes another version of what seems to be the same issue. No noise on trainer.
> 
> Tarmac 2018 S-Works Frame, DA 9100 Mechanical Group Set 53/39 & 11-28T sprockets, with rebuilt wheel from 9000 rim brake free hub 36 spoke. When the bike was built new 2 years ago I noticed under high torque I would get some rear derailleur noise. It seems to be indexed correctly no noise and shifts crisply on the stand. This went away and I forgot about it. Then I just recently replaced all of the drive chain...rings, chain, cassette. I did the install myself and the chain is exact same length/link etc. Now the noise is back, it's on both rings and the lowest gears (the last larger 3-4 sprockets), mostly up hills under higher power although I can reproduce under heavy load on flats. One theory I want to put out there is that the dish of this wheel seems to be slightly offcenter...the bike shop did this, and I've not addressed it. I've read about bike frame flex and that could be some of it too but I'm hoping that is very minor component. Any other thoughts?


Well, chain noise could have gone away before, as the chain and sprockets wore in. The chain becomes laterally flexible and absorbs the flex induced by the cogs. 

The chain hits at more of an angle on the outer cogs, hence more noise. It might be rubbing on the outer [under shift] or inner [overshift] front derailleur cage. Check for loose crank bolts and BB play.

Agree with cx, the rear derailleur wouldn't induce noise in the drive train. The flex would be somewhere between the rear wheel cogs and the chainrings on the BB. Badly worn rear wheel bearings or a slightly under-tensioned spoke, might make noise under power, but you won't feel it in the chain. So could slightly loose headset and loose front wheel bearings or quick release.

Eliminate the possible causes one by one, huh? 

The bike will track better if the rear wheel is centered. Use a centering tool. Forget trying to use the brake blocks or chain stays. Run a string from the rear wheel rim touching in two places to the front wheel rim touching in two places. If the string doesn't touch both wheels in two places, the rear rim is off center or the wheel isn't fully seated in the dropouts. 

Front wheels never go off center because they aren't dished or loaded up torsionally. Rear wheels tend to go out of dish and move to the left. 'Zat what you got?


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## johnlwarner (Mar 19, 2012)

Definitely noise under power on larger rear cogs, noise is coming from rear derailleur. I looked at FD last night and adjusted there was some rubbing there, I adjusted and in cases where there is no FD rubbing I still get the noise almost sounds like skipping combined with rumble popping and/or grind. If looking over the seat facing the the rear wheel looking down the seat tube through each chain stay the rim is slightly shifted over to the left rather than in the center.


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## johnlwarner (Mar 19, 2012)

I agree with your assessment about the wearing. I think wheel flex is a possible component of this, I've had brake rub from flex on this same wheel. I agree also that the derailleur itself is not causing the issue, it's likely more of a chain alignment and flex issue. Chain rings and sprockets are new and tight. headset is tight as well. I'll have to try your string trick when I put the back wheel on.


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## 202cycle (Sep 13, 2011)

Wheel dish will have absolutely NOTHING to do with this. Now, if the wheel is not in the frame straight, you could get some derailleur alignment issues in the larger cogs. Check the spring on the QR skewer to make sure it is not backward. I see this way more than I'd like, if the big side of the spring is on the inside, the axle won't sit in the dropout correctly.


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## cxwrench (Nov 9, 2004)

johnlwarner said:


> I agree with your assessment about the wearing. * I think wheel flex is a possible component of this*, I've had brake rub from flex on this same wheel. I agree also that the derailleur itself is not causing the issue, it's likely more of a chain alignment and flex issue. Chain rings and sprockets are new and tight. headset is tight as well. I'll have to try your string trick when I put the back wheel on.


No...it isn't. Read post 24 from 202cycle.


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## johnlwarner (Mar 19, 2012)

Ok great, thanks. I think that I usually pay attention to that but I'll still check. One thing related to this is that when I put the hub in the dropouts there seems to be a lot of play and it requires me manually aligning the rim evenly between the brake calipers while tightening the skewer not to get brake rub. I can't just place the hub between the dropouts and tighten the skewer to the ~90 degree (by feel point) and clamp to have the rim be dead center between the brake caliper.

------
I checked the skewer springs tonight...both sides had the smaller diameter on the inside.


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## duriel (Oct 10, 2013)

troll alert


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