Need mechanical advice: shifting problems

Hey all …

I’m having a mystery problem with my road bike and I’d like to solicit opinions from any mechanics, or the mechanically inclined. I am about to take the bike to my 3rd different mechanic, and the first two were unable to diagnose/fix it.

The problem is a combination of lazy shifting, skipping cogs and/or the chain rattling on certain sprockets. My normally excellent LBS, whom I’ve worked with on all my bikes for 8+ years, adjusted it 3 times before I took it elsewhere to get a second opinion. I just picked it up yesterday from the 2nd place, and the problem persists. The symptoms of the problem have been moved up and down the cassette, but they’ve never been eliminated.

Here are the relevant details on the bike:

Bike: Firefly Titanium Disc
Bottom Bracket: Chris King threaded, recently serviced
Groupset: Shimano Dura Ace 9100 2x mechanical, hydraulic
Cassette: SRAM Red 11-32 — brand new, just replaced
Chain: Shimano Dura-Ace 11-speed, less than 200 miles on it

Pulley wheels were recently upgraded to Kogel oversized pulleys; new derailleur hanger was installed due to the original being slightly bent.

The bike was fully tuned-up in March, at which point the BB was fully serviced, the new pulleys, chain and derailleur hanger were installed. From April through mid-June the it shifted great. About 3-4 weeks ago it started to have shifting problems and I took it in for what I thought was going to be a minor derailleur adjustment … however, they couldn’t seem to get it quite right. At this point it was identified that I might need a new cassette after 18k miles on the original cassette (which was also a SRAM Red 11-32). The new cassette was purchased and installed, and while the problem slightly improved, it did not solve it. I took the bike back for them to inspect the cables and housing, which they did … but still not solved. I then took it to a second shop to be worked on and a fresh set of eyes … just picked it up yesterday and I would say it’s worse if anything.

— Has anyone had a mystery shifting problem that couldn’t be easily solved?
— Do derailleurs wear out? (Mine is the original Dura Ace, bike purchased in 2018 and has the same amount of miles on it as the original cassette)
— Should I ask a mechanic to start over with all new cables/housing?
— Anything else I’m not thinking of?

Thanks in advance for any input/insight.

**Also, if any of you are in the Chicago area and have a genius mechanic you might recommend, please feel free to send me a PM. My LBS has a sterling reputation with high-end bikes … but they weren’t able to solve.

I’m not a mechanic so this is a totally random guess, but could the new derailleur hanger be bent already?


That’s my guess. Are you running the SRAM over an Ultegra because of weight? Never been a fan of mixing drivetrain components.

They do, but I’d start with that cassette.

Yes, I probably would have done that first, at least as a way of eliminating the issue. Shifting issues are the worst, good luck.


Takes a long time. I’m still running XTR from 2006, and it just a strip and clean and grease of main pivot spring after it had collected gunk over the years. Good as new. Jockeys wheels are consumable and need replacing every now and again.

Just a thought after my last sentence above, are the guide and tension jockey wheels the right way round on your derailleur?. The guide pulley (jockey wheel) has lateral side to side movement to align with cassette cog.


That’s the first thing I thought of as well. But, no … it’s not bent.

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Good question. I’m running the SRAM 11-32 because at the time the Dura Ace groupset did not go lower than 11-28, and I wanted the climbing gears. I am not sure why the builder (Firefly) recommended Red vs. Ultegra, but they did … and that’s why I went with the Red cassette. It worked flawlessly for ~4 years, and I never had a problem with it that an adjustment or a new chain couldn’t fix.

I’m getting a new cable installed as I write this, so hopefully that will solve it.


Hey. First thing that jumps out to me is the chain. I usually match the chain to the cassette. So in this instance I would have run a SRAM chain with that cassette. I have a GRX RD, SRAM Chain, and run both an Ultegra cassette and a SRAM Red 11-32. No problems with either. If after the new cable is installed that doesn’t fix it you might want to just try a SRAM red chain and see if that is it.


Looks like DA caps out at 11-30 maybe? I’d want the 32 as well - it’s a curious choice from the builder, seems like you all had good results up until now, though. I’d still consider trying an ultegra cassette if the easier fixes don’t work.

Something else that I’ve seen happen in Shimano shifters is cables eventually fray and break down, eventually completely failing and making the replacement much harder than is needed. If the cable is still hanging on by a thread or a few, that will obviously make shifting poor.

Let us know how it goes!

Send pics!

Is this VS?
What you can do:

  1. Put the chain in little ring / big sprocket or big little. Get the chain out of the way. Eyeup the middle cog in back. Line up 2-3 teeth with your eye. You should be looking right between the two rings in front.
  2. Lazy shifting sounds like shift cable housing. There’s probably a kink or some variability in how the cable housing end caps are seated. Make sure the shifter cable is coming into the shifter without a big buildup of goo. Make sure you’re using the same shifter cable as the housing/endcaps: Shimano is 1.6mm, SRAM & Jagwire are 1.5mm. Also, those shimano cables can clog up with the hairy lube. Next time it goes in, have them install a Jagwire elite super polished cable.
  3. See if the chainrings/spider aren’t moving around too much. Some minimal movement is ok, but you shouldn’t see a lot of wobble - Chainrings can be bent or spider wobble. Make sure there’s not side to side play in the crank spindle.
  4. Cassette - sometimes when there are bite marks on the freehub the cassette might not be tight. Look to see if the cogs wobble. Take a screwdriver and see if you move the middle cogs relative to one another - they should be tight.
  5. Cassette 2 - Is it doing this in a given rear cog regularly? I had an issue on a XDR 12sp 10-36 where I only had a tick in a given middle cog 2x a revolution of the rear wheel. Turned out I there wasn’t enough clearance between two cogs. I needed to file down the cog tooth just below the ticking tooth. The link was snapping onto the tooth in one spot. You need to put a piece of tape on the cassette to give it a ‘North’, so you can tell where the tick is relative to the tape marker. Eagle cassette tolerance and clicking | Mountain Bike Reviews Forum
  6. Rear wheel not staying in the frame. I had an issue once where the rear wheel just wouldn’t stay in the frame. In the hill climbing gears, the wheel would jack itself out of the dropouts. While off the bike, put the bike in the lowest gear, clamp down on the front brake and hold the saddle with your other hand, and push down with your foot on a pedal as hard as you can. The rear wheel shouldn’t displace.
  7. Chainline 2. You might be missing a spacer and the chainline is just a bit out of line. This would give you more issues on either the inner most cogs or the outer most.

I can look at it on the weekend if you’re out of ideas. I’m in the NW burbs, but usually need to run errands to the North side every now and then.

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My guess is the mix of SRAM cassette and shimano chain. While it works it might not be quite as smooth as a shimano cassette.

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I’d say is probably the oversize pulleys and the chain/cassette combo.
Did you have problems before “upgrading” to the Kogel pulleys? I put upgrading in quotations, because in my opinion oversize pulleys are not an upgrade. They are hard to get the shifting right. A lot of people will get them right, but is not going to be as easy and smooth as the Dura-Ace pulleys.

Just follow Kogel’s instructions to the letter and make sure the chain length and b-gap is set right. You might need to play slightly with the b-gap on the rear derailleur. Then, I will change to SRAM Red 11-speed chain or a XTR 12-speed chain might work nicely too.


(Thanks to everyone for weighing in and giving me some tips)

The 3rd mechanic I visited (yesterday) found two problems: 1) I asked him to replace the cable, and when he did he found a small kink in it, and 2) the chain was put on wrong. Apparently Shimano chains are uni-directional (I didn’t know that) — and I find it almost incredible that the other mechanics working on the bike didn’t notice.

Lesson: as someone mentioned above, I think when you have a “mystery” shifting problem, start with replacing the cable no matter how new it is.


Did those two problems sort out your shifting issue?

Asking the obvious as it is not stated whether your shifting issues have been removed.

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Housing, too. If the cable got kinked permanently somehow, its likely that the housing run isn’t great anymore, either.

Now would be a time to politely share the post-fix info with your preferred #1 mechanic, but not in an “I told you so” sort of way. Also, try to find a way for the fixinig #3 mechanic to get a little more of your business.

Glad you got your issue resolved batwood. I will add one more thing to look at for anyone that refers to this thread in the future. I’ve had several times where my shift cable has broken inside the brifters (mostly mid 2000’s Ultegra left-sides). When this happens it can sometimes be a real pain to get out all the little pieces of wire that frayed inside prior to complete breakage. Similar to a kinked wire or housing this can lead to spots of higher resistance that hold excess tension that doesn’t release until you shift a 2nd time.

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PS, there is a special, ultra flexy cable housing for the last bit into the rear derailer. If you are swapping wheels out alot (onto and off of trainer?) then that housing might be getting bent or kinked, especially if its just regular housing, not the flexy one.

Opinions wanted, will go by the LBS tomorrow if I can’t figure it out.

I started having trouble getting into the smallest cog, and while trying to use the barrel adjuster if I turn it enough to get into the smallest cog I can no longer get into the biggest one.

Should I disconnect the cable at the real derailleur and try to start over and index again? Seems unlikely that it would be an issue with the limit screws.

It’s an 800 series 11spd GRX if that info helps.


  • Yup. When all else fails, start over at the beginning of the setup process.

Coupled with that, consider the following:

  • Have you considered a possible “crash” that may have bent the RD hanger? When a good setup goes bad, this is worth a close look.

  • Once you disconnect the cable, verify the alignment of the High Limit Screw to the small cog, and push the RD by hand up to the Low Limit Screw for the large cog. Each should engage fully without excess noise. If there is an issue, a screw adjustment may be appropriate.

  • Before reconnecting the cable, make sure to run the barrel adjuster all the way in to start, and I like to unscrew it 1 full turn. This gives the most space for adding tension, but leaves a bit for reducing tension in the rare event that you over-pull when setting the cable at the start.

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barrel adjuster all the way to the start - is that towards the smallest cog or the largest?

Righty-Tighty all the way, since it’s essentially just a fancy “screw”.