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Rattling Chain

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Old 01-11-19, 02:05 PM
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roadie2019
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Rattling Chain

Hello,

My chain rattles. Here's the situation:

I am running a newly installed groupset (Shimano Ultegra R8000). When I have my bike in the work stand and rotate the crank, with the chain in any cog from 1 to 4, in either chainring, the chain makes a horrible rattling noise. Like someone shaking a box of rocks. What I've done so far:
  1. Check to make sure the chain isn't rubbing against any part of the derailleurs or frame.
  2. Checked chain length
  3. Installed a different chain
  4. Installed a different cassette
  5. Checked chainring bolts
  6. adjusted rear derailleur B-screw, limits, and tension
  7. checked that hub and cassette were tight
  8. lubed chain
  9. checked that crankset was installed properly, with no lateral play
  10. checked that bottom bracket was installed properly and bearings were good
  11. tried different set of wheels
Nothing seems to work. Bear in mind all parts are brand new and this only happens when in the first 4 cogs. I am using a KMC X11SL chain. It should also be noted that shifting performance does not seem to be affected.


Does anyone have any suggestions?

Thank you.

Last edited by roadie2019; 01-11-19 at 02:27 PM.
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Old 01-11-19, 04:22 PM
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AndrewJB
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I am assuming the rattling is from the rear DR.
The first thing that comes to mind is you didn't thread the chain through the jockey wheels correctly. There is a tab of sorts on the upper jockey wheel frame that some folks often run the chain over instead of under. But I would imagine you would have major issues in all gears in that case.
The next is...did you install all required spacers on the cassette?
I have two bikes that came with the R8000 group set. In both cases I downloaded the install & set-up manuals from the Shimano web site, assumed they were set-up wrong to start with (they were), and just started from the beginning, step by step. Properly set-up they are smooth, and a joy to ride.
Other than that something might be bent or damaged.
Hopefully someone with a whole lot more knowledge and experience than me will chime in...
Can you post pictures or video?.
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Old 01-11-19, 04:28 PM
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roadie2019
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Originally Posted by AndrewJB View Post
I am assuming the rattling is from the rear DR.
The first thing that comes to mind is you didn't thread the chain through the jockey wheels correctly. There is a tab of sorts on the upper jockey wheel frame that some folks often run the chain over instead of under. But I would imagine you would have major issues in all gears in that case.
The next is...did you install all required spacers on the cassette?
Yes, the chain is threaded correctly through the rear derailleur cage. No spacers are need for the cassette, as I am using an 11 speed cassette on an 11 speed hub. It is hard to tell where exactly the noise is coming from, but if I had to guess, my inclination would be to point at the chainrings. When the chain is making noise, like I described above, I feel slight vibrations in the crankset.

It's almost as if the chain isn't sitting properly on the chainrings and rotating the crankset causes the chain to vibrate. Perhaps the chainring is mis-shaped? Though not enough to be visible to the naked eye, but enough to cause the chain to vibrate against it?

Or perhaps the crankset isn't straight, thus affecting the chainline, which in turn cause the chain to be at a weird angle?

Last edited by roadie2019; 01-11-19 at 04:34 PM.
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Old 01-11-19, 04:42 PM
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AndrewJB
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I had a difficult time with the front DR on one of the bikes, I ended up going as far as removing the DR and starting from the beginning, there is a very specific process of steps, and items you have to set, to get it right.
I will add, for someone like me that just got back into cycling recently and had not worked on bikes for awhile, the manuals are a little vague sometimes, assuming I guess that the user is more experienced (I was not).
So take your time, don't jump around, follow the steps, and check as you go.
You may have done all that, and apologies if this isn't your first rodeo

Pics or videos would help...I see you only have two posts so you may not be able to do that yet.

One more thing, if you have a brazed on mount, the R8000 front DR has a screw that is "buried" in the middle of the DR that adjusts the angle of the DR. It has to be in contact with a solid surface. Shimano provides a small curved metal piece that attaches with double sided tape to be used if the bike doesn't have a solid bearing surface, very important on CF frames, but needed for any frame that doesn't have a solid metal accommodation. Also the tape should be applied to one edge of the plate so the screw pushes the plate onto a solid part of the frame, not on the tape.

Last edited by AndrewJB; 01-11-19 at 05:04 PM.
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Old 01-11-19, 06:18 PM
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Chances are it's a chain-line issue, a tooth profile issue or simply that the new parts have a few sharp edges that haven't had time to wear off yet. If the chain is jumping I'd watch how it's engaging at the chainrings on the crank as the jumping motion could simply be the narrow sideplates of the chain popping down into place!
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Old 01-11-19, 06:20 PM
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Do you have a smartphone? Take 30 seconds of video and host it on a free site like imgur. Then post it here.
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