Rear derailleur clicking

So when I have my rear disc wheel on, and I shift down to the hardest/smallest cog on my cassette, every 5-6 revolutions it “clicks” where it seems to skip up a gear and then go back down. It’s a constant pedal pedal pedal pedal pedal…CLICK, click…pedal pedal pedal pedal CLICK…click.

How do I fix this? I just changed cassettes but it happened on my old one too. I’m on an 11-28 now, and I indexed the gears so they will shift up and down the cassette smoothly. It only happens when I’m riding. If it’s on my bike stand and I’m rolling through the gears, it’s fine. Is does the high/low limit need to be adjusted? Or something else?

Thanks for any insight

At a guess the barrel adjuster may need a 1/4 turn (either clockwise or anti -clockwise) as it sounds like the chain may be trying to jump up or down a gear. It could be shifting perfectly in the stand but with a little bit of frame flex during a ride it can sometimes be marginally out. With some frames even in a ride the difference between standing up and sitting down frame flex can change things marginally again.

I should have mentioned, it’s di2. I did the adjustment mode, which let me index it. But if it shifts between gears fine, and then jumps when in the smallest cog during rides, wondering if that’s an indication it’s not indexed, or if the limits need to be adjusted.

If it shifts fine everywhere other than the highest or lowest gear, you are likely having an issue with the “Limit screw” on the related end.

As such, the “High Limit” is related to any issue on the smallest cog of the cassette. Checking that alignment is probably what I would suggest next.

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I think Di2 is supposed to make those marginal adjustments Id guess it is the limits then needing adjusted but I’m no Di2 expert.

Di2 does apply “trim” to the front derailleur in coordination with where the rear derailleur is in the range.

But it does not handle issues if the limit screws are not aligned properly for the max/min gear on the cassette. It’s possible that the trainer and his regular wheel have slightly different alignment that could result in needing to adjust the limit screws. It’s not overly common, but based on the symptoms (only bad at the high gear), the limit screw could need a tweak, and that is a manual operation.

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I have an old school wheel-on trainer. If I’m in the hardest gear, it’ll jump too.

(But I don’t get into the hardest gear that often on the trainer).

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Yeah, got off with thinking trainer is involved. Either way, you have what is most likely a limit screw issue, so inspect and adjust that appropriately and see if that addresses the issue.

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Take a pic of the RD in the lowest gear.

Is the chain routed through the cage right - not hitting the tabs? Is the chain hitting the chain as it S through there. Did you forget to put a spacer behind the crank if you removed and installed it? Is there a pin sticking out of the chain?

If it’s nothing already mentioned, every 5 revolutions of the pedals suggests quick link to me…

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If any of the above suggestions don’t help, I’d suggest checking the derailleur hanger alignment. I often find when mine is out slightly, my shifting is good in the gears near the cog I made the Di2 fine adjustments (I believe Shimano recommends 4th or 5th from the top) but shifting suffers at the extents, e.g 28t or 11t (cogs furthest from the adjustment location).

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Good catch on that. We could probably do some gear-inch math and figure out if 5 revolutions is correct.

Good call! It really sounds like an H limit screw adjustment issue but checking the derailleur hanger alignment is always a good idea if you’ve got a tool & know how to use it.

  1. Make sure all interfaces have enough grease. (pivots, cassette to free hub, hub to brake disc, etc.)
  2. Make sure the chain is lubed properly.
  3. Check B screw.
  4. Check H and L limit screws.
  5. Check hanger alignment.
  6. Check indexing.
  7. Check your chain and especially the link is good.
  8. Make sure you use the same torque on the axle every time. This is really important and most people ignore this. I always use a torque wrench on my thru’ axles.

I don’t know that it’s 5…but it seems rhythmic.

If it’s rhythmic and occurs at the extreme end of the cassette I’d be looking at the chain first.

Quick link might be installed the wrong way around.

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Not to steal your thread, but mine started ‘clicking‘ tonight too. Sure it’s just a cable tension or hanger issue.

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If you have a quick link on the chain, check it. Replace it…see if that’s the problem. My first thought, there is a ‘sticky link’ in your chain. If you have a spare chain you could just swap them out and see if the problem goes away.

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It could also be a stiff link. Happens, among other causes, when the chain is removed and replaced using a new pin (or “recycled”one, I know, you will end up in eternal fire if you do that).