Rival AXS 1x 11tooth cog skipping

[ghammer]

So I got a gravel bike, and a friend sent me a (used) Rival AXS group.

After some finagling at the LBS (frame is from 2018/2019, so minor differences for disc brakes, frame is fit for quick release wheels), and slapping a 11-42 SRAM cassette, I was good to go. It's 11-42 because the frame and wheels are quick release, the wheels are HED Ardennes and the hubs are Chris King 11 speed, so a 10 tooth cog wouldn't fit without major $$ hub surgery.

The hydraulic brakes were an eye opener, and the wireless works marvelously. As an example, a riding partner said "I noticed you shift a lot less with this setup". He was wrong, I shift the same, the group is THAT quiet compared to mechanical.

I love that bike.

Anyway, the cassette and chain are new. Both Rival. But the 11-tooth cog skips. I don't know why. It skips like when we install a new chain on a worn cassette. Allegedly everything is aligned, as it was built at my LBS.

Anything I should look into?

Thanks!

Gus

[prototoast]

Rival AXS is 12 speed. Sram makes an 11-44 12 speed cassette, but doesn't make an 11-42.

So sounds like something is mismatched? What chain are you using?

[ghammer]

The cassette and chain are sram, sram does make a 11-42 cassette. Sorry, it's 11-44, look:

https://www.biketiresdirect.com/prod...MaAvFTEALw_wcB

[mjf]

Originally Posted by ghammer

So I got a gravel bike, and a friend sent me a (used) Rival AXS group.

After some finagling at the LBS (frame is from 2018/2019, so minor differences for disc brakes, frame is fit for quick release wheels), and slapping a 11-42 SRAM cassette, I was good to go. It's 11-42 because the frame and wheels are quick release, the wheels are HED Ardennes and the hubs are Chris King 11 speed, so a 10 tooth cog wouldn't fit without major $$ hub surgery.

The hydraulic brakes were an eye opener, and the wireless works marvelously. As an example, a riding partner said "I noticed you shift a lot less with this setup". He was wrong, I shift the same, the group is THAT quiet compared to mechanical.

I love that bike.

Anyway, the cassette and chain are new. Both Rival. But the 11-tooth cog skips. I don't know why. It skips like when we install a new chain on a worn cassette. Allegedly everything is aligned, as it was built at my LBS.

Anything I should look into?

Thanks!

Gus

Alignment and h/l/b limits would be my first two points to check.

[prototoast]

Originally Posted by ghammer

The cassette and chain are sram, sram does make a 11-42 cassette. Sorry, it's 11-44, look:

https://www.biketiresdirect.com/prod...MaAvFTEALw_wcB

Okay, thanks for clarifying it's an 11-44 cassette.

If it's fine in every other cog except the 11, I would check the limit screw.

[November Dave]

Make sure you have a lock ring for 11t on there. Lots of tool boxes/parts drawers have old 12t lock rings kicking around and they cause issues with 11t cogs.

Other than that, limit and b-screw and be sure the derailleur hanger is dead straight and secure.

[buckfifty]

Originally Posted by prototoast

Okay, thanks for clarifying it's an 11-44 cassette.

If it's fine in every other cog except the 11, I would check the limit screw.

https://www.youtube.com/watch?v=fO9FuZroc8E

sram's gap tool is super handy. I believe sram has the 3d print file to print one out yourself

[kppolich]

Hanger Alignment
Limits
B Gap

[yinzerniner]

Originally Posted by ghammer

Allegedly everything is aligned, as it was built at my LBS.

That's a pretty big assumption to make, especially since they were retrofitting the group onto an existing bike/wheels which can be a huge time suck which in turn is a revenue loss leader. Did the LBS charge you a decently high amount, or did they just charge the typical low "tune up" fee? Because if it was the latter then can easily see them not checking a few specific alignment setup points in order to hit their time cap. The bleeding, bedding and alignment of the calipers to your wheels alone could take 45mins+ if the caliper mounts and QR dropouts aren't perfectly aligned.

For the cassette, with 12s and up the tolerances are so tight that the other steps mentioned (hanger alignment, b screw/gap setup, limit setup) can all be culprits. But first step would be to redo the RD setup from scratch on a stand - ie shift to second largest cog, adjust RD positioning/centering visually, check gap and adjust b screw accordingly, then shift up and down cassette to see if any noise is present in any of the cogs. If there's noise present in any cogs then use the micro-adjust to see if going up/down a tiny amount helps with noise.
Setup video:
https://youtu.be/Bx-kB7rNFJQ?si=F1ZhrqtpdVY9cFX9&t=251

When you mention "skipping" is it just noise, or is the chain skipping over the cog teeth under power? It sounds it skipping under power but not entirely clear.

Also, do you know what crankset and/or BB setup you're using? If the chainline isn't setup correctly that could lead to some noise/skipping.

Another thing to note: you mentioned that the wheels and rear dropout is QR, and sometimes due to the design of the DS dropout there might not be enough room between the chainstays and the cassette, or the cassette might have been installed too far outward if the previous freehub spacer wasn't fully removed. A few Shimano 11s HG freehub cassettes required a 1mm or 1.85mm spacer, and it's possible the LBS installed the new cassette without removing the spacer.

[oldpotatoe]

Originally Posted by November Dave

Make sure you have a lock ring for 11t on there. Lots of tool boxes/parts drawers have old 12t lock rings kicking around and they cause issues with 11t cogs.

Other than that, limit and b-screw and be sure the derailleur hanger is dead straight and secure.

That's the first thing that I thought of, a 12s locking. Or perhaps a Wipperman snap-link installed upside down.

[Dave]

Check the RD hanger alignment. Use the SRAM B gap tool to set the upper jockey pulley clearance. The 44 requires shifting into the 38, then placing tool over the upper jockey and setting a 10mm gap with the 44. After that, back out the limit screws and see if a micro adjust click one way or the other helps, then return the limit screws. Chain length is big/big plus 2 inches. I use the chain length formula with 2 inches add, not 1.

[charliedid]

Is it a Rival AXS XPLR rear derailleur?