Horrible noise in small gears - 12 speed SRAM

Indexing? I’ve had similar noise with 1 or 2 cogs down low (SRAM AXS Force) and indexing was the solution…

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?