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I just replaced the jockey wheels on my 6800 ultegra rear derailleur. I noticed some clicking on a couple of the cogs on the the cassette. Upon further investigation, I discovered it was the new guide pulley wheel that was getting stuck and sucking up the chain for a moment before it released which created the click. I purchased the correct replacement jockey wheels on amazon and they look legit (I purchased a fake shimano chain on amazon in the past, so I'm skeptical of authenticity). The chain has maybe 200 miles on it.

My question is, has anyone else experienced this issue with new jockey wheels? My thinking is that after a couple rides the wheel will break it and and round off ever so slightly as to not have the crisp new edges which are catching the chain slightly. It's only happening on two of the cassette cogs and only on, I believe, one of the jockey wheel teeth. Other than waiting for it to break in, I could file down the tooth slightly.. This doesn't seem right..

Let me know what you think and what your experience has been in the past which replacing jockey wheels. If it is a fake shimano part, I was thinking the best way would be to compare the bearing manufacturer. The marking on the bearing is -NMB R-1760D THAILAND-. Does this sound like a legit bearing shimano would use? I will link a video showing the issue. If you look carefully, the chain is sticking to new guide pulley, but only happens when in the 2nd and 3rd largest cassette cogs.

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    If it’s sticking on only a couple gears I would think the issue is more around alignment or indexing of the mech and/or cage rather than any sort of break in period.
    – Hursey
    Commented Apr 8, 2023 at 19:17
  • Might try filming aligned with the chain path from behind to see the side to side position; maybe the chain is catching on something on the side like the jockey wheel cage.
    – Armand
    Commented Apr 8, 2023 at 21:26

3 Answers 3

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It should never happen if all the parts are genuine, not excessively worn, and correctly adjusted. To me, it seems that one of those conditions is not met.

Assuming the parts are genuine, I'd start by checking if the jockey wheels are installed correctly ( the one with side play must be installed on top). Then make sure that the derailleur hanger is not bent (a special tool will be required for that, but a bike shop can help you in this regard). Finally, index your gears - it can be that the gear cable is just too tight.

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  • I torqued the guide jockey to spec and there really is no play. Are you sure ultegra 6800 guide pulley should have play?
    – alrob
    Commented Apr 10, 2023 at 4:33
  • @alrob - yes, there should be a slight amount of play in the upper pulley that's meant to compensate for possible misalignment of the derailleur hanger or uneven cable pull. If you used a standard torque wrench instead of a T-handle hex key, it is possible that you inadvertantly bent the hanger itself.
    – Paweł
    Commented Apr 10, 2023 at 14:15
  • I totally forgot I even made this post, but you were right. It was the indexing. It was perfectly indexed before getting the new jockey wheel, but that tiny bit of material was enough to throw it out. I felt pretty silly after realizing it was just a slight indexing issue.
    – alrob
    Commented Oct 11, 2023 at 1:08
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I suspect the root cause is tolerances on the jockey wheel, chain link, or both.

Find a pen that will make a visible mark on your chain and jockey wheel. A whiteout pen or a chalk pen for writing on glass will be ideal, permanent markers like sharpies tend to not work.

Make a mark on That one link and That one jockeywheel tooth. Then work the chain just like in your video.

You're trying to tell if the cause is a narrower gap in that one chain link, or if its a slightly wide tooth in the jockey wheel, or both lining up. To fix it, you may need to file the inside of that link with a needle file to remove burrs, or thin down a subtle bulge on the jockey wheel, like a casting defect.

The gap between noises can help too - there's only 11 teeth on a jockey wheel, compared to ~100 links on a chain. Presuming a 40-50 tooth chainring, the catch would happens ~20 times per crank revolution. Which is a lot.

I had a stiff link in my chain, would bend normally but not back on itself, so it clonked everytime it went past the top jockey and bent backward. Since mine was a chain link, it clonked every ~2 crank revolutions while riding.

Good luck!

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    I did what you suggested with marking the cog and link and found that it was happening on different links and cog teeth. I've continued to ride with it and have noticed now the clicks are much softer and subtler, so I think you were corrected about the tolerances. I bet another ride or two and all the clicks will be gone. I'm just avoiding the second biggest cassette ring since that is the one that had the worst clicks.
    – alrob
    Commented Apr 23, 2023 at 0:52
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The ultegra jockey wheels are not identical. The jockey wheel with the larger teeth goes on the top of the derailleur cage.

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  • thanks. I do have the jockey wheels in the correct positions.
    – alrob
    Commented Apr 10, 2023 at 4:32
  • Do you have the rotation on the bottom jockey wheel correct?
    – P. Barney
    Commented Apr 10, 2023 at 17:52
  • yes, the bottom jockey wheel is fine. It's only the guide pulley that has this issue.
    – alrob
    Commented Apr 23, 2023 at 0:45

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