Eagle AXS shifting issues

Weird one which i can’t seem to solve so wondering if anyone has any ideas. All gear shift find apart from going from 12-11. Done the b tension, aligned with micro shift but for some reason cannot get 12-11 to shift. Everything else works fine!

Anyone experienced it or have any ideas how to fix it?

Usually with a bent derailleur hanger AXS has problems with a gear or two. So first make sure the hanger is straight. Other uncommon issues could be the cassette is loose or the chain is too long/short. Lastly, if you’ve crashed on the derailleur side, you may have bent the derailleur’s parallelogram. If this is the case then there’s no fix and you’ll have to replace.

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Its a pretty new bike so the hanger ‘should’ be ok. Chain length i thought i measured it correctly as per srams recommendations but will check. The derailleur was second hand is there a way to check if it is bent?

No way to check but if there’s scratches on the derailleur that’s an indication. I’m on my third AXS derailleur in 4 years due to crashes. Also, I wouldn’t just assume the hanger is straight. AXS/Eagle has very tight tolerances and the slightest misalignment can throw of shifting.

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If everything checks out straight…

Have seen a few frames over the years where a small spacer or shim between the derailleur mounting bolt and hanger is required. That will move the derailleur outbound in relation to the cassette and allow the chain to drop into the smallest cog. Once that is sorted you can adjust for the other cogs to index.

In the USA, McMaster Carr sells a variety of shims.

Check the app and make sure they’re in the right gear. It could be off due to the adjustments

Also try a smaller b gap. I run mine a few mm smaller than spec, SRAM seems to do best with as small a b gap as you can get without interference when shifting to the larger cogs.

Edit: never mind, this won’t help you go from 12-11. I thought you meant 11-12.

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This is going up 12-11 now down so i doubt a shim would help.

Actually a smaller b gap could still help you. It makes it easier to shift to harder gears, so you could potentially micro adjust the derailleur inboard enough to make the 12-11 shift without losing performance shifting to smaller cogs.

Also a perfectly new/straight hanger doesn’t necessarily mean the hanger is “square” to the cassette: if the frame’s hanger attachment interface isn’t perfect you might actually need to bend any new hanger to get it perfectly aligned.

The way you wrote the original question, and responses, are unclear. So you are getting different ideas on what to check.

To clarify, the problem is a rough shift, or no shift, when going UP from the 11t cog to the 12t cog?

Does that mean the 10 to 11 shifts solidly and properly both up and down and the 12 shifts Down to the 11 properly too? Assuming you using SRAM 10-50 or 10-52 cassette and matching chain?

We all love a good drive train mystery so help us help you :slight_smile:

It seems OP says “down” for going to harder gears, so I’ve adjusted my langauge to eliminate the words up and down. The shift from 12 to 11 is the bad one.

Wait apologies got my numbers wrong it think, my bad!

Yep so every gear works fine up and down apart from shifting from 1 (smallest - 10 teeth) to 2 (next smallest - 11 teeth). It just grates and doesn’t mvoe up until you press again then jumps to 3. Does that make sense?

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Ha…those are expensive crashes…

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Yes it does.

One of the posters above suggested making sure the electronics are set up correctly. I agree and would reset the system and go through the install procedure again. SRAM and others have YouTube videos on the entire process. Sometimes in process of setting up and fine tuning strange things can happen so it’s worth just trying again from the beginning.

Also, do a careful inspection of the cassette. A bent cog could cause shifting issues. Also make sure the cassette is installed correctly and is tightened appropriately. I would remove, clean the cassette body and reinstall.

Also check the master link on the chain for correct orientation.

There was already good advice about making sure the hanger is both straight and parallel and to inspect the derailleur cage for issues.

I have seen a couple cases where everything checked out, nothing was obviously wrong, but changing out the derailleur fixed problematic shifting issues. Let’s hope you just have a set-up problem. But, if you can borrow a know good derailleur and try it, that can help define what is wrong. I know people don’t just have spare AXS derailleurs sitting on the shelf so likely need a good friend or a shop to help with that.

TL;DR Hopefully its not a damaged mech. Assuming all the parts are OK, I would take the system apart, re-set the electronics, and reinstall cassette, chain and derailleur. Double check each step for correct orientation of parts and visually inspect for anything that might be bent or damaged.

Be methodical and good luck!

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Had very similar problem, turned out worn pully wheels on derailleur

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