Ultegra CS-R800 11 Speed Cassette - Runs Rough

[charliedid]

11-34 Ultegra CS-R800 11 Speed Cassette

Ultegra chain and drivetrain. All new-ish. 11 spd freehub and using supplied spacer.

Anyone else have this issue? Noisy in general and rough feeling. Also found another issue doing research where the third largest cog(27) will make a click every revolution. This seems widely referenced on the web. I had not noticed but a quick check reveals this as well.

Anyone with this issue find a solution? It shifts just fine and is not really noticeable except when cleaning chain etc. But now I know...

Different chain? Different cassette? Just shut up and ride?

[eddief]

It rides fine on the road with no issues but you hear something when cleaning? Is the bike upside down when you clean the chain?

[charliedid]

It rides fine on the road with no issues but you hear something when cleaning? Is the bike upside down when you clean the chain?

Hi Eddie

No bike is in a stand when cleaning.

Thanks

[eddief]

curious.
Hi Eddie

No bike is in a stand when cleaning.

Thanks

[charliedid]

curious.

This is where I found the 27 tooth skip issue

https://www.competitivecyclist.com/shimano-ultegra-cs-hg800-cassette#review

https://www.youtube.com/watch?v=YHHSqxqM49k&feature=youtu.be

[eddief]

that video did not show the person adjusting anything while turning the cranks. seems like a chain line or cable tension adjust issue...or a defect :).

[charliedid]

that video did not show the person adjusting anything while turning the cranks. seems like a chain line or cable tension adjust issue...or a defect :).

That guy was er something...

Yeah I'm convinced it's some manufacturing issue.

What I want to know is do I need a new chain or a new cassette?

[John H.]

I would try a new chain- But I did have an 8000 cassette that had a bad cog. Mine was 3rd one down from the 34, so 27?
Never ran right on multiple bikes with different chains. Shimano warrantied it and gave me a new cassette.

[charliedid]

that video did not show the person adjusting anything while turning the cranks. seems like a chain line or cable tension adjust issue...or a defect :).

Sorry

58cm Gunnar Sport. R8000 derailleur. The correct one.

[charliedid]

I would try a new chain- But I did have an 8000 cassette that had a bad cog. Mine was 3rd one down from the 34, so 27?
Never ran right on multiple bikes with different chains. Shimano warrantied it and gave me a new cassette.

Of course. I was going to buy it wholesale from Shimano and got a deal here for basically the same money and the right length crank arms.

I guess I could press them on it. Which cassette did they give in replacement a newer run of the same?

[ColonelJLloyd]

I would try a new chain.

Same. And not a Shimano chain.

[charliedid]

Same. And not a Shimano chain.

If I had to just jump right in I'd try a KMC chain first. Have you had the issue or know that a non Shimano chain works?

I wonder if this has anything to do with this cassette being able to run on both 10 and 11 speed FHB?

Who knows.

[DRZRM]

You mean HG800 right? The 11 speed 11-34 that can fit a 9-11 speed MTB hub or 11 speed road hub? I get a bit of this too, known issue. Did Shimano ever deal with it? Are new ones better?

[charliedid]

You mean HG800 right? The 11 speed 11-34 that can fit a 9-11 speed MTB hub or 11 speed road hub? I get a bit of this too, known issue. Did Shimano ever deal with it? Are new ones better?

Yes sir.

[ColonelJLloyd]

If I had to just jump right in I'd try a KMC chain first. Have you had the issue or know that a non Shimano chain works?

Never had this issue, no.

I personally use a SRAM 1170 with a 105 level 11-32 11s cassette and it is quieter and smoother than the Ultegra chain it replaced. Maybe that was just a bad chain, but it was noisy and broke at three different links on a short tour, whereas the two KMC quick links held fine.

[ryker]

11-34 Ultegra CS-R800 11 Speed Cassette

Ultegra chain and drivetrain. All new-ish. 11 spd freehub and using supplied spacer.

Anyone else have this issue? Noisy in general and rough feeling. Also found another issue doing research where the third largest cog(27) will make a click every revolution. This seems widely referenced on the web. I had not noticed but a quick check reveals this as well.

Anyone with this issue find a solution? It shifts just fine and is not really noticeable except when cleaning chain etc. But now I know...

Different chain? Different cassette? Just shut up and ride?

I installed the same 11-34 cassette yesterday (with a new DA chain and Ultegra RD) and had the same disappointing experience. Shifts fine but noisy in general coming from a DA cassette and RD.

I experienced the same click problem on the 27T cog however mine happened every second revolution of the cassette. It always happened on the same tooth but only when picking up an inner link (hence every second revolution). Position of the FD didn't change anything. The interim solution was to file the backside of the adjacent tooth on the 25T cog and the problem more or less went away.

I feel like some careful use of thin cassette spacers/shims (e.g. 0.1mm) in specific locations might improve the situation however whether it compromises shifting remains to be seen. Or perhaps a chain with slightly different thickness/geometry.

[charliedid]

I installed the same 11-34 cassette yesterday (with a new DA chain and Ultegra RD) and had the same disappointing experience. Shifts fine but noisy in general coming from a DA cassette and RD.

I experienced the same click problem on the 27T cog however mine happened every second revolution of the cassette. It always happened on the same tooth but only when picking up an inner link (hence every second revolution). Position of the FD didn't change anything. The interim solution was to file the backside of the adjacent tooth on the 25T cog and the problem more or less went away.

I feel like some careful use of thin cassette spacers/shims (e.g. 0.1mm) in specific locations might improve the situation however whether it compromises shifting remains to be seen. Or perhaps a chain with slightly different thickness/geometry.

Hmm no surprise. Truthfully I hate Shimano chain and have never really used them over the years much. I don't know why exactly but always used KMC SRAM Sachs chains.

I guess I will go and try a KMC chain and see what happens later. I loathe futzy bike stuff. Good for you for trying to make it work.

Thanks

[charliedid]

Never had this issue, no.

I personally use a SRAM 1170 with a 105 level 11-32 11s cassette and it is quieter and smoother than the Ultegra chain it replaced. Maybe that was just a bad chain, but it was noisy and broke at three different links on a short tour, whereas the two KMC quick links held fine.

I'm gonna try a KMC or 1170 chain and see what happens.

[fa63]

I just bought a bike which came with a 11-34 cassette / Shimano chain (both brand new), and I am finding it to be noisier than I prefer as well. I will keep an eye on this thread to see if a different chain makes things better.

[zmalwo]

might be a bent teeth.

[charliedid]

might be a bent teeth.

If only it was that easy. It's a known issue, I just can't find the easy fix so I need to just try something. So it goes

Thx

[GregL]

If only it was that easy. It's a known issue, I just can't find the easy fix so I need to just try something. So it goes
Is this issue isolated just to certain production runs? I ask because I've had an HG800 11-34 cassette on my gravel bike for the past year with zero issues. It runs perfectly with Shimano 5800 shifters/derailleurs, 6800 crankset (46/34 chainrings), Dura Ace chain, and KMC chain connector. I just spent a week riding the roads (gravel and paved) of Acadia National Park and it performed perfectly.

Greg

[charliedid]

Is this issue isolated just to certain production runs? I ask because I've had an HG800 11-34 cassette on my gravel bike for the past year with zero issues. It runs perfectly with Shimano 5800 shifters/derailleurs, 6800 crankset (46/34 chainrings), Dura Ace chain, and KMC chain connector. I just spent a week riding the roads (gravel and paved) of Acadia National Park and it performed perfectly.

Greg

Not sure entirely.

Seems the 27 tooth issue was fixed for some with a replacement others not so much. I have that issue plus a general rough feeling especially in first three cogs. I can even see it jump a tiny bit.

That said it's not a huge problem but I am a bit of princess now that I know it. Especially the 27T thing. It must be fixed! :-)

It shifts flawlessly under all conditions.

[charliedid]

I just bought a bike which came with a 11-34 cassette / Shimano chain (both brand new), and I am finding it to be noisier than I prefer as well. I will keep an eye on this thread to see if a different chain makes things better.

I'll def. post what I find.

[NHAero]

I have these cassettes on the Anderson and the Firefly. The Anderson drivetrain is close to silent. The Firefly is noticeably noisier, but not just in one gear. Both running KMC 11s chains, both reasonably new, same lube. Anderson is Ultegra RD, Firefly is Dura Ace. Similar total chain wrap (44-33 on the Anderson, 46-34 on the FF, both have the 1st cog changed to a 12T 6800 series.)

I thought it was likely to be the chainrings, as the FF has SRAM Red and the Anderson has TA.

[TheseGoTo11]

I've had the same issue with my HG800 clicking on the 27 cog from day one. Running with Shimano 11 speed chain. No issues with R8000 11-30 cassette or 6800 11-28 cassette.

[ryker]

I've had the same issue with my HG800 clicking on the 27 cog from day one. Running with Shimano 11 speed chain. No issues with R8000 11-30 cassette or 6800 11-28 cassette.

For testing I swapped in an 11-32 without changing my limits, cable tension, or B-tension settings (i.e. no changes). It shifts perfectly through the entire range, has no oddball issues in single gears, and seems to be much quieter.

[weiwentg]

I have one 11-34 cassette, and I can't say it's run rough. However, while trying to confirm which cog was the 27t one, I came across this Cyclingtips article (https://cyclingtips.com/2018/03/shimano-ultegra-hg-800-11-34t-cassette-review/), which said

In the early days of testing, I experienced a bit of unexplained roughness and noise in certain gears with both this and a new R8000 cassette. Frankly I can’t explain it, and even where everything was set up perfectly, one or two gears (typically around the 17T sprocket) made more noise than they should. Thankfully the cassette eventually wore in, and the noise soon disappeared.

[DRZRM]

Yeah, I think this is just an issue with the 27 cog, if someone has the issue with their top three cogs I think it is something else. If you fix it with a different chain, please let us know, I'd be more than happy to change. It's a gear I use a lot, and even micro adjusting the Di2 does nothing for it. Seems like a company as big as Shimano should have better QC.

[charliedid]

I've had the same issue with my HG800 clicking on the 27 cog from day one. Running with Shimano 11 speed chain. No issues with R8000 11-30 cassette or 6800 11-28 cassette.

For testing I swapped in an 11-32 without changing my limits, cable tension, or B-tension settings (i.e. no changes). It shifts perfectly through the entire range, has no oddball issues in single gears, and seems to be much quieter.

Ah ha!

So it appears more likely that I should keep the chain and swap the cassette?

TY both.

[NHAero]

Even weirder - I had one of these cassettes on my Anderson for a few hundred miles, maybe a bit more. Swapped it out for an 11-40 for D2R2. Just swapped it back on last night. Before, no clicking, and now it clicks! Same bike and all bits the same.

[fmradio516]

To the OP: I dont remember the circumstances, but I remember feeling a similar "runs rough" drivetrain a few times. I could feel like some kind of binding through the pedals and there is a kind of droney noise associated with it.

I dont remember what I did to fix it, unfortunately.

[NHAero]

So I put it up in the stand and watching carefully could see that there are two teeth on the 27T cog itself, not an adjacent cog, that lift the chain momentarily. I fussed with the cable adjuster and eventually made it stop. Fussy!

[josephr]

I'm gonna try a KMC or 1170 chain and see what happens.

my experience with KMC chains is that they're noisy the first 50-100 miles...of course, all my bikes are 10sp, so dunno if 11, but they quiet down after a break-in period. good chain!

[SlowPokePete]

Having this exact frustrating problem now.

SPP

[NHAero]

I have this cassette on two bikes. In the stand one can see the chain pick up on a tooth in the third largest cog, then taking up a smidgin more tension in the cable makes it go away. Only to re-appear a few hundred miles later, and repeat the
process.

Having this exact frustrating problem now.

SPP

[charliedid]

Having this exact frustrating problem now.

SPP

New cassette? My eventually broke-in or so it seems. Either way I never notice.

[SlowPokePete]

New cassette? My eventually broke-in or so it seams. Either way I never notice.

Brand new cassette and chain (chainrings, too).

I can watch it happen in the bike stand right before my eyes.

And, of course, hear it while I'm pedaling.

and it seems the R8000 cassette is unavailable in 11-34 to even replace it.

Probably around 200 miles tops on it...hoping it will just go away (but I've heard that before).



SPP

[fmradio516]

ive also got the clicky thing on my 11s campy bike. really annoying considering everything is brand new. shoulda stuck with 10s :)

[oldpotatoe]

ive also got the clicky thing on my 11s campy bike. really annoying considering everything is brand new. shoulda stuck with 10s :)

Campag or shimano cassette?

[charliedid]

Brand new cassette and chain (chainrings, too).

I can watch it happen in the bike stand right before my eyes.

And, of course, hear it while I'm pedaling.

and it seems the R8000 cassette is unavailable in 11-34 to even replace it.

Probably around 200 miles tops on it...hoping it will just go away (but I've heard that before).



SPP

You get the "jump" on the second biggest cog and overall rough feeling always?

[SlowPokePete]

With chain 3rd cog down, one link will ride up momentarily on the same tooth (marked with Sharpie) of the 4th cog down.

Happens with big as well as small chainring up front (also new).

Runs fine (smooth and quiet) in all other gears, including the 4th cog down.

SPP

[oldpotatoe]

With chain 3rd cog down, one link will ride up momentarily on the same tooth (marked with Sharpie) of the 4th cog down.

Happens with big as well as small chainring up front (also new).

Runs fine (smooth and quiet) in all other gears, including the 4th cog down.

SPP

Bend, file that tooth...

[charliedid]

Bend, file that tooth...

Yeah I might try that too. I don't know what the hells going on with these but I almost hit the cogs with a wire wheel to try and "break it in" and then just for got about it.

[NHAero]

Pete, I'm running KMC chains, and this happens on my HG800 cassettes, and the solution is always a tad more cable tension.

Brand new cassette and chain (chainrings, too).

I can watch it happen in the bike stand right before my eyes.

And, of course, hear it while I'm pedaling.

and it seems the R8000 cassette is unavailable in 11-34 to even replace it.

Probably around 200 miles tops on it...hoping it will just go away (but I've heard that before).



SPP

[tylercheung]

Dunno if my experience generalizes, but I've fiddled around w/ the rear cable tension - I baseically overtighten it on the small cog until it clicks then gradually loosen until it doesn't click. the 3rd-cog click has gone away since I did that. Runs quiet now! (although not as quiet as the bike w/ the Athena group! I have to admit...)

[charliedid]

Cable tension fix noted.

[benb]

What exact wheel/ hub is this?

There are very few setups where you’re supposed to use the spacer with an 11 speed cassette on an 11-speed freehub. 11 speed is the wider cassette.

It could just be the spacer.

I literally just screwed this up a couple days ago the other way around. I have an 11 speed Mavic wheel and I stuck a 10 speed shimano cassette on it and only used the Mavic spacer when I actually need the Mavic one plus the 1mm Shimano spacer.

It is doing the same thing you’re talking about. Too much noise but mostly shifts perfectly, just not quite as perfect as it should with a brand new cassette plus chain.

[Stainomo]

The shimano 11-34 cassettes, both 105 and Ultegra level, are all 10speed width and need a spacer on a 11 speed freehub.

[benb]

Is that just the 11-34?

[Stainomo]

Is that just the 11-34?
Yes

[Matthew]

I recently installed a NOS 6800 group. Besides hoping my crankset doesn't explode at any second I also have a few cogs on the cassette that are chatty. 4th. and 5th. cogs from the bottom especially. The other cogs are quieter than a Billie Eilish vocal. Shifting is perfect. Last Sunday I literally spent 1 1/2 hours with my ear to the cassette adjusting my barrel adjuster waiting for the least amount of noise in a particular gear. Got it to what I thought was the best adjustment. Lubed the chain and virtually no noise. Get out on the road and after a number of miles the noise is back but probably the best it's been since initial install. Should I look at getting a KMC chain too? If so which model? I do think the gold ones are cool!!! Thanks for any advice!!!

[cgates66]

I'm running an 11-25 R8000 cassette and while not "rough", it's not as quiet as my prior DA7800 (which to me may have been the most technically perfect drivetrain due to direct-exit vs. bent shifter cables - yes yes the new stuff looks somewhat tidier). And it took some fiddling to get it "reasonable".

I personally have found Shimano chains are noisy compared to say KMC. They quiet down with some wet lube somewhat, but I've never had a perfect silent Shimano chain.

On the R8000:
1) Make sure the high / low limits are set properly;
2) Make sure your derailleur hanger is straight;
3) Fiddle with the tension. Mine seems to like "somewhat tighter" as opposed to somewhat loose. Shimano recommends the 3rd-cog technique, and I tried that to get a baseline, but then spent some time working the chain through the gears and played with the tension to get the best compromise.
4) The old 1/4-turn thing no applies. Mine went from noisy to quieter with 1/8th of a turn!
5) If too loose, the chain will skip.

The tolerances and what not seem tight on 11-speed, so it might be hard to get it right.

If none of that works, others may have better ideas.

[benb]

Yes

Crazy. Is that Shimano having a MTB standard for 11 speed and a separate standard for road 11 speed and then just relabeling an MTB cassette for road instead of making one with road spacing?

I’m trying to remember didn’t they do 11 speed first in XTR or something like that?

Super weird. I miss 9 speed.

[charliedid]

Crazy. Is that Shimano having a MTB standard for 11 speed and a separate standard for road 11 speed and then just relabeling an MTB cassette for road instead of making one with road spacing?

I’m trying to remember didn’t they do 11 speed first in XTR or something like that?

Super weird. I miss 9 speed.

I believe that is correct.

[Big Dan]

I've had good luck with KMC X11.93 chains and 6800 cassettes.

[charliedid]

I wonder if 11 spd Shimano MTB cassettes' teeth have different profiles than 11 speed road? Designed for wider spacing, q-factor etc...

Thinking outloud.

[fmradio516]

Campag or shimano cassette?

Campag Chorus. KMC x11SL chain

[NHAero]

I have these CS-HG800 11 speed 11-34 cassettes on three bikes. I'm tired of the finicky setting and periodic re-adjustment of the cable tension to keep the clicking from occurring. This evening I took one of the cassettes apart, cleaned it well, and took a file to the two teeth on the 25T cog that lift the chain temporarily and cause the annoying click. I marked the two teeth with a Sharpie but once apart it wasn't necessary, because those two teeth are shiny at the leading edge of the tip from the occurrence of this problem.

In the workstand the click is gone, and I'll see if that holds true on the road, and for longer than a few rides. If so, I'm going to modify the other ones, and the two I'm hoarding in the drawer.

[SlowPokePete]

I have these CS-HG800 11 speed 11-34 cassettes on three bikes. I'm tired of the finicky setting and periodic re-adjustment of the cable tension to keep the clicking from occurring. This evening I took one of the cassettes apart, cleaned it well, and took a file to the two teeth on the 25T cog that lift the chain temporarily and cause the annoying click. I marked the two teeth with a Sharpie but once apart it wasn't necessary, because those two teeth are shiny at the leading edge of the tip from the occurrence of this problem.

In the workstand the click is gone, and I'll see if that holds true on the road, and for longer than a few rides. If so, I'm going to modify the other ones, and the two I'm hoarding in the drawer.

pro move.

SPP

[charliedid]

I have these CS-HG800 11 speed 11-34 cassettes on three bikes. I'm tired of the finicky setting and periodic re-adjustment of the cable tension to keep the clicking from occurring. This evening I took one of the cassettes apart, cleaned it well, and took a file to the two teeth on the 25T cog that lift the chain temporarily and cause the annoying click. I marked the two teeth with a Sharpie but once apart it wasn't necessary, because those two teeth are shiny at the leading edge of the tip from the occurrence of this problem.

In the workstand the click is gone, and I'll see if that holds true on the road, and for longer than a few rides. If so, I'm going to modify the other ones, and the two I'm hoarding in the drawer.

Hero

[NHAero]

20 miles today. Note that I'm also upping my chain lube game at the same time, so this bike got a thorough drivetrain cleaning including the chain and then re-lubed with Squirt. In any case, not a single click from the cassette in the third cog. We'll see if that continues!

[charliedid]

20 miles today. Note that I'm also upping my chain lube game at the same time, so this bike got a thorough drivetrain cleaning including the chain and then re-lubed with Squirt. In any case, not a single click from the cassette in the third cog. We'll see if that continues!

I think you fixed it

[oldpotatoe]

I think you fixed it
Yeah I'm convinced it's some manufacturing issue.


Copy to shimano....never mind, they don't care...:)

[chrisroph]

my shimano 11-32 and sram 11-36 run fine. haven't tried a shimano 11-34.

[NHAero]

Yes, all they make is trash. Thank you for the reminder!


Copy to shimano....never mind, they don't care...:)

[NHAero]

Third ride today post-filing, still no clicks. I'm cleaning all my drivetrains and last night did the same light file job on the Firefly cassette, and when I clean it, the Litespeed one is next. Then the two spares in the drawer!

[NHAero]

168 miles over the past 6 days, no more clicking. This is a solution to the problem and takes two minutes once the cassette is off the wheel and disassembled.

[ryker]

168 miles over the past 6 days, no more clicking. This is a solution to the problem and takes two minutes once the cassette is off the wheel and disassembled.

I have done the same (on page 2 of this thread!) and it was a durable fix.

[Tim Porter]

I recently had to use a file to show one of the teeth on the 27 cog who is boss and the problem went away with about two minutes of effort. Did not need to remove the wheel from the bike. You can watch the tooth hold the chain up momentarily and then it "chunks" into place. Just shape the tooth a tiny bit.

[oldpotatoe]

Yes, all they make is trash. Thank you for the reminder!

It's not like you are the only person to see an issue with this cogset.
https://forum.bikeradar.com/discussion/13095263/cog-spacing-problem-on-ultegra-hg800-cassette

[reuben]

Third ride today post-filing, still no clicks. I'm cleaning all my drivetrains and last night did the same light file job on the Firefly cassette, and when I clean it, the Litespeed one is next. Then the two spares in the drawer!

This is the sign of a true craftsman. I would have used a 3 pound hammer, blowtorch, and crows foot.

[NHAero]

Of course not. However, you are such a valued contributor to this forum, and yet the constant sniping at anything not made by Campagnolo is frankly tiresome and a misuse of perfectly good electrons.

It's not like you are the only person to see an issue with this cogset.
https://forum.bikeradar.com/discussion/13095263/cog-spacing-problem-on-ultegra-hg800-cassette

[NHAero]

Me too, but in this case, the crows were on strike! Plan B was required.

This is the sign of a true craftsman. I would have used a 3 pound hammer, blowtorch, and crows foot.

[chrisroph]

I love peter's posts, I love campagnolo (before 11 speed) and I love shimano, now.

[oldpotatoe]

Of course not. However, you are such a valued contributor to this forum, and yet the constant sniping at anything not made by Campagnolo is frankly tiresome and a misuse of perfectly good electrons.

SORRY, yup, Campagnolo fan-boy thru and thru-Guilty!! But geez, bike stuff, toys...and lotsa electrons..don't think we're gonna run out..:)

But bikes, not covid or politics or whatever..small beans...

[Krenovian]

I have an offending 27 tooth cog on a 11-34 cassette. Those of you of you that have taken a file to the teeth, what aspect of the teeth or tooth are you filing? Not sure this will work on my cassette as it sounds more like the chain is rubbing on multiple teeth as if the derailleur is out of adjustment. No cable tension to adjust as it is a DI2 system which I’ve attempted to adjust with no luck. Shifting is good, no rubbing on any other cogs.


Sent from my iPad using Tapatalk

[NHAero]

Put the bike in a stand so you can place the chain on the 27T cog. Then slowly advance the chain. What happens is that two of the "tallest" teeth, roughly diametrically apart on the 25T cog, catch the outer edge of the side plates and temporarily lift the chain, then it snaps back into place. Look at the Youtube link in the 5th post in this thread.

If you advance the chain slowly enough you'll see the chain catch. Mark those two teeth on the 25T cog with a Sharpie. Pull the cassette, and gently file an angle on the leading edge of those two teeth. On my cassette, I had enough miles that those teeth actually showed a shiny spot from the rubbing.

You can do a bit of trial and error, you shouldn't need to remove much - I made like half dozen easy passes with the file.


I have an offending 27 tooth cog on a 11-34 cassette. Those of you of you that have taken a file to the teeth, what aspect of the teeth or tooth are you filing? Not sure this will work on my cassette as it sounds more like the chain is rubbing on multiple teeth as if the derailleur is out of adjustment. No cable tension to adjust as it is a DI2 system which I’ve attempted to adjust with no luck. Shifting is good, no rubbing on any other cogs.


Sent from my iPad using Tapatalk

[steveadore]

Put the bike in a stand so you can place the chain on the 27T cog. Then slowly advance the chain. What happens is that two of the "tallest" teeth, roughly diametrically apart on the 25T cog, catch the outer edge of the side plates and temporarily lift the chain, then it snaps back into place. Look at the Youtube link in the 5th post in this thread.

If you advance the chain slowly enough you'll see the chain catch. Mark those two teeth on the 25T cog with a Sharpie. Pull the cassette, and gently file an angle on the leading edge of those two teeth. On my cassette, I had enough miles that those teeth actually showed a shiny spot from the rubbing.

You can do a bit of trial and error, you shouldn't need to remove much - I made like half dozen easy passes with the file.

Still struggling with the same issue (27T cog clicking due to tall teeth on 25T cog lifting the outer chain plates). Is the filing a foolproof and efficient solution with no tradeoffs (e.g. causing skipping or affecting cassette longevity)?

Btw, when you say that the leading edge of the offending teeth needs to be filed at an angle, do you mean just at the top of the teeth (top 2-3mm)?

[BdaGhisallo]

Shimano have quietly updated the Ultegra cassette and released a CS-R8101 iteration.

Hopefully, this one addresses the issues that have been encountered with the original R8100 cassette.

The part numbers for the 8101 cassette are:

11-30 ICSR810112130

11-34 ICSR810112134

[steveadore]

Shimano have quietly updated the Ultegra cassette and released a CS-R8101 iteration.

Hopefully, this one addresses the issues that have been encountered with the original R8100 cassette.

The part numbers for the 8101 cassette are:

11-30 ICSR810112130

11-34 ICSR810112134

That's true, but this thread is primarily about the Ultegra level 11 speed cassette (in my case, the HG800), whereas the 8101 is a 12 speed cassette

[BdaGhisallo]

That's true, but this thread is primarily about the Ultegra level 11 speed cassette (in my case, the HG800), whereas the 8101 is a 12 speed cassette

My mistake. I'd never actually heard of any issues with the 11sp cassettes, only the newer 12sp ones.

I should read a little better!

[steveadore]

My mistake. I'd never actually heard of any issues with the 11sp cassettes, only the newer 12sp ones.

I should read a little better!

I have no experience with 12sp but read about them when I was looking for info about my 11sp cassette. It's the HG800 11-34 cassette and the issue is with the 27T cog large chainring combination (the adjacent 25T cog has a couple of taller teeth that are too close to the 27T and lift the chain at certain positions of a revolution). From what I've read, it's quite a widespread issue, but unfortunately it hasn't been officially acknowledged, so there's no updated cassette

[dddd]

I have a sneaky suspicion that these sort of problems are more related to indexing error, caused by the sharp sort of bends that the cable endures going into the shifter-area routing, especially during installation.

Where many assemblers force the tight loop of cable into the cable housing port only after the entire length of the cable has been fed through the shifter's spool area, the more-correct installation feeds the tip end of the cable into the cable housing initially, so that the tightly-bent loop that gets forcefully stuffed into the cable housing/port is the part of the cable that will later be cut off aft of the rear derailer.
And the cable is always better fed into the shifter than pulled through it, reducing the chance of the cable getting bent/curled (this having to do with the higher tension force caused by "cable-wrap gripping forces" of the sort used to secure ropes around posts in shipping yards).

Curled cable performs poorly in terms of transmitting the shifter's motion to the derailer, as it acts like a spring (adding elasticity to the cabling).

Having a bent cable running through the shifter is a recipe for imprecise indexing, as any permanent bends will not allow the cable to follow the exact same path in all of the gear positions.

I have over the years fixed many mystery indexing faults by using thinner 1.1mm cable, since it's thinner diameter is significantly more easily pulled straight along or adjacent to a curved path, and because it's thinner diameter is significantly less likely to become bent or curled following any given bend radius that it's installation forces it to conform to.

It's also possible that forceful pre-stretching of the installed cable might incur some bend local to one of the shifter's tight-radius guide features, which then flows less than gracefully into the spool area of the shifter as the larger cogs are engaged (again, a thinner 1.1mm cable is less vulnerable to becoming bent following any given radius at any given tension level).

It's possible to modify a cog's teeth to accommodate any slight indexing error, but perhaps better to go to the source of the problem.

[steveadore]

I have a sneaky suspicion that these sort of problems are more related to indexing error, caused by the sharp sort of bends that the cable endures going into the shifter-area routing, especially during installation.

Where many assemblers force the tight loop of cable into the cable housing port only after the entire length of the cable has been fed through the shifter's spool area, the more-correct installation feeds the tip end of the cable into the cable housing initially, so that the tightly-bent loop that gets forcefully stuffed into the cable housing/port is the part of the cable that will later be cut off aft of the rear derailer.
And the cable is always better fed into the shifter than pulled through it, reducing the chance of the cable getting bent/curled (this having to do with the higher tension force caused by "cable-wrap gripping forces" of the sort used to secure ropes around posts in shipping yards).

Curled cable performs poorly in terms of transmitting the shifter's motion to the derailer, as it acts like a spring (adding elasticity to the cabling).

Having a bent cable running through the shifter is a recipe for imprecise indexing, as any permanent bends will not allow the cable to follow the exact same path in all of the gear positions.

I have over the years fixed many mystery indexing faults by using thinner 1.1mm cable, since it's thinner diameter is significantly more easily pulled straight along or adjacent to a curved path, and because it's thinner diameter is significantly less likely to become bent or curled following any given bend radius that it's installation forces it to conform to.

It's also possible that forceful pre-stretching of the installed cable might incur some bend local to one of the shifter's tight-radius guide features, which then flows less than gracefully into the spool area of the shifter as the larger cogs are engaged (again, a thinner 1.1mm cable is less vulnerable to becoming bent following any given radius at any given tension level).

It's possible to modify a cog's teeth to accommodate any slight indexing error, but perhaps better to go to the source of the problem.

But how do you explain that indexing is perfect with 10 cogs out of 11, including both the next smaller and bigger cogs? And most people have experienced issues with the one 27T cog. Sure, chain angle has sth. to do with, as the angle of the chain makes it easier for it to catch on some of the taller teeth of the 25T cog, which are too close (both physically in terms of space and also in diameter/tooth count) to the 27T when the chain is on the latter

[charliedid]

I have a sneaky suspicion that these sort of problems are more related to indexing error, caused by the sharp sort of bends that the cable endures going into the shifter-area routing, especially during installation.

Where many assemblers force the tight loop of cable into the cable housing port only after the entire length of the cable has been fed through the shifter's spool area, the more-correct installation feeds the tip end of the cable into the cable housing initially, so that the tightly-bent loop that gets forcefully stuffed into the cable housing/port is the part of the cable that will later be cut off aft of the rear derailer.
And the cable is always better fed into the shifter than pulled through it, reducing the chance of the cable getting bent/curled (this having to do with the higher tension force caused by "cable-wrap gripping forces" of the sort used to secure ropes around posts in shipping yards).

Curled cable performs poorly in terms of transmitting the shifter's motion to the derailer, as it acts like a spring (adding elasticity to the cabling).

Having a bent cable running through the shifter is a recipe for imprecise indexing, as any permanent bends will not allow the cable to follow the exact same path in all of the gear positions.

I have over the years fixed many mystery indexing faults by using thinner 1.1mm cable, since it's thinner diameter is significantly more easily pulled straight along or adjacent to a curved path, and because it's thinner diameter is significantly less likely to become bent or curled following any given bend radius that it's installation forces it to conform to.

It's also possible that forceful pre-stretching of the installed cable might incur some bend local to one of the shifter's tight-radius guide features, which then flows less than gracefully into the spool area of the shifter as the larger cogs are engaged (again, a thinner 1.1mm cable is less vulnerable to becoming bent following any given radius at any given tension level).

It's possible to modify a cog's teeth to accommodate any slight indexing error, but perhaps better to go to the source of the problem.

You must be correct, based on the sheer number of words you wrote.

[oldpotatoe]

You must be correct, based on the sheer number of words you wrote.

Yup, good inner wire routing is certainly key but with one cog that's angry on this cassette, probably not inner wire install.

[steveadore]

It has been suggested to me that I should experiment with slightly higher B-screw tension. Theoretically, that might be helpful in keeping the chain further away at the bottom (6 o'clock position) from the cassette and thus prevent the chain from catching on the adjacent cog's tall teeth at pickup.
I'm not convinced, but it seems to have worked for some folks with the same cassette, so I'm willing to give it a try

[NHAero]

This has been asked and answered upthread. I have several of the HG800 cassette in service on three bikes and multiple wheelsets. Look carefully at which teeth of the offending cog lift the chain, and use a file to ease that top leading edge. I have about 10,000 miles on these cassettes and no clicking or fiddling with cable tension. It is IMO a design flaw in the product but easily resolved.

[steveadore]

This has been asked and answered upthread. I have several of the HG800 cassette in service on three bikes and multiple wheelsets. Look carefully at which teeth of the offending cog lift the chain, and use a file to ease that top leading edge. I have about 10,000 miles on these cassettes and no clicking or fiddling with cable tension. It is IMO a design flaw in the product but easily resolved.

That will be my next step probably but I need to get a thin needle file first

[NHAero]

That will be my next step probably but I need to get a thin needle file first

I used a small flat file (enlighten me what a needle file is please)

[jadmt]

I used a small flat file (enlighten me what a needle file is please)
https://www.amazon.com/Piece-Precision-Needle-File-Set/dp/B006N3EPKE

[jadmt]

funny I never noticed it on mine (I have 3 with the this cassette) until reading this post. sure as ***** all do it on the 27 tooth lol. my newest cassette has about 1300 miles and the other two somewhere around 3500 apiece. 2 are less than a year old so probably pretty recent stock and the oldest not much more than a year old.

[steveadore]

funny I never noticed it on mine (I have 3 with the this cassette) until reading this post. sure as ***** all do it on the 27 tooth lol. my newest cassette has about 1300 miles and the other two somewhere around 3500 apiece. 2 are less than a year old so probably pretty recent stock and the oldest not much more than a year old.

Mine are new stock too (bought in June).