Horrible noise in small gears - 12 speed SRAM


Please send the side pic of the RD in the 10th cog. Also, get a pic of the top pulley

SL7 with Force groupset with Red 10-33 cassette on both the bike and Kickr V5/2020.

Outside I don’t notice a grinding noise but 46x12 and 46x11 and 46x10 gearing is used when riding above say 23mph so wind noise is high and unlikely to hear it.

A couple weeks ago I rode in Zwift / sim mode and noticed a grinding noise in 10 and 11 and maybe 12 on the cassette. Didn’t spend a lot of time powering down hills in Zwift so it wasn’t a big deal. Looking like I’ll need to use Zwift again this week and will spend some time inspecting my indoor setup.

Don’t have the answer but experiencing the same issue. On the lower 3 cogs the sound is awful, but only on the trainer.

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Check the cassette is definitely on tight. I had this with a new cassette and it was driving me nuts. Then I looked down and it looked like the small cogs were bent. On closer inspection they just weren’t on tight enough so they were moving around. I removed a spacer and all good.

That looks good.

  1. I don’t see any witness marks.
    -on the derailleur hanger, but I only see the rear of it. Check the front of the hanger for marks.
    -The outside-flat/top of some links might have some scrapes. Those can only really touch the RD arm by the top pulley, the RD hanger, and the FD. Might just be par for the course.

  2. You’ve got the DS and NDS end caps in the right side? The end caps are screwed on all the way. Maybe take your Thru axle out, use it as a gauge to see how deep it goes on a rear wheel (how much pops out the other end if you stick in in there without the bike, then see if that matches the trainer without the bike on there. While the bike is off, see if you can wobble the cassette or any of the gears.

  3. You’ve got the XDR (6/9mm vs 12mm ID) https://support.garmin.com/en-US/?contactOverride=true&faq=h7IJL6xUhy4a1XkuHUDxQ6&productID=690886&searchQuery=axle&tab=topics You’re probably using a Type2, so you probably cant even get a Type 1 on there.

  4. Do you have the right spacers on your BB? I assume DUB wide; the SL7 is a BSA 68 ? https://www.sram.com/globalassets/document-hierarchy/compatibility-map/road/dub-choose-a-road-bottom-bracket-compatibility-map.pdf

  5. Your RD took a whack right by the adjustment screws. Check to make sure the b-bolt (the bolt that goes into the RD Hanger) doesn’t tilt or slide. Those go bad sometimes. https://www.amazon.com/SRAM-Rival-Derailleur-B-Bolt-Black/dp/B09L6PW6HN

It seems like a lot of rubbing is goioing onThe noise magically goes away when you get it into the middle of the cassette, that’s why I think it might be the chainline (bottom bracket spacers) or the freehub body. The cassette pins (what ties the 12th gear to the 1st gear on an XD cassette) can also be loose. You can try these and see if it helps https://www.competitivecyclist.com/sram-cassette-stealth-ring-set-for-xg-1290

So I decided to pull the mech apart and check all the pulleys were the right way round etc and found some damage on one of the bearing covers and the hanger.

Not sure how or why it’s happened but cleaning and being sure to put the pulley wheels in the right was has made it much better. Upper pulley doesn’t spin well so I think I need to order new bearing covers.

Much better now, but not perfect

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You can still clearly hear the rhythmic sound. That is pretty much what I hear on my Campagnolo drivetrain (only in the 11).

Now I’m curious to work on it to see if I can make it go away.

Is this only on the 10?

Curious if anyone got to the bottom of this… having the exact same issue with a sram force group set - new chains rings / new cassette / new chain and can’t figure it out.

I took it to the bike store and they did some adjusting but it’s still the same — they’ve since told me I need to let the chain break in…

I’m having this same issue — anyone find a solution?

The bike shop looked at it and said the new chain just needs to break in — but it sounds pretty terrible in the last 3 cogs.

I just swapped new cassette / chainrings / chain - so seems odd this noise would be normal. Dropped sram a ticket and will see what they say.

That entirely does not sound normal. It clearly sounds like you know what you are doing from a mechanical standpoint but after seeing the abrasion on the pulley cage it made me wonder if your lower pulley wheel has been meshing correctly with the chain, considering the narrow/wide tooth arrangement. I’ve of the most important factors to installing a SRAM Flattop chain on an AXS derailleur. I have two bikes each running Red AXS, one disc one rim brake and do not have noise like that at all. Force Flattop chains on each, always waxed.

Exact same issue with my Force AXS 12s. On the road, I can even feel the grinding in the smallest gears. I do run it on a 12s rival cassette. Would be very interested in the root cause of the issue.

Thought I’d put this here rather than start a new thread. Hope it helps someone…

New bike last week equipped with SRAM Force AXS. Have been having a terrible time with the noise, grinding in certain gears and indexing in general. I’d get the top half of the cassette adjusted ok and the bottom wouldn’t shift and vice versa.

Finally I got smart and removed the cassette and installed my older one. Perfect. Turns out the cassette is a little warped (not straight). The shop was great and it will get warrantied.


Circling back here - returned that force cassette and got a new one. Same issue. Contacted SRAM with that video and they asked me to take a video of the bike in the stand spinning the wheel (where of course the sound was lessened but still there). SRAM said it sounded normal.

Returned that one and bought a red cassette on eBay, no issue. Ridiculous. Pretty disappointed.

Another one here with a similar problem.

Gears sound dreadful like either the chain is not lubed, or it’s rubbing or its hooking up on a worn chainring. Only in the small chainring though, the large chainring across the range is fine.

All the items are brand new…

Sounds like a bag of spanners! Like others, I am looking at Di2 for all the faffing that this 12 speed SRAM seems to entail. Grrrrrrr!!!

If I didn’t know better, I’d swear you guys were talking about some Chinese branded Ali Express groupsets. :angry:

Ha ha! Conversely I’ve never had any issue with the Sensah or LTwoo stuff I have tried and the many cheap Chinese cassettes I’ve tried!

The knock off Dura ace chains were a different and not entirely amusing matter however!

I’d assume that Chinese “branded” products, like Sensah or LTwoo have a good quality control process in place. They are trying to build a big brand image, and poor quality will come back to bite them.

Whereas fake parts don’t need much QC, there is no brand image that could get harmed, apart from the one of the faked brand, which the fakers don’t care about.

I also think that some “fake” parts are actually real parts that failed QC for one reason or the other, so might have any type of defect.

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