SRAM Rival XPLR eTap AXS Rear derailleur issue

I have put my Trek Checkpoint SL6 gravel bike on my Tacx (a new bike and a new trainer) and have had a major issue with the rear derailleur. Since I'm relatively new to all of this I'm not sure what the cause of the issue is, but have included a video of what is happening. To summarize, I get a strange chain "jolt" on the lowest cog, with most of the other gears working fine until i get all the way to the largest cog. On the largest cog I get more of a chain placement issue which I can probably correct with the micro adjustment feature on the derailleur. The chain jolt at the bottom I can't quite pin down. Hopefully someone here has some more technical insight into what could be happening and how I can fix it. The video has a slow motion section near the end where you can hopefully see the issue more clearly.

youtu.be/lDBtaw3QWL0

0 Scillonian over 1 year ago

Dominik said:
On the largest cog I get more of a chain placement issue which I can probably correct with the micro adjustment feature on the derailleur.

You should be able to correct this by adjustment of the read derailleur. The chain is trying to climb onto the next cog but failing to and the jolt comes from it dropping back down to the current cog.

In theory is you are using the same model cassette on the trainer as you use on the wheel then no readjustments should be needed but in practice some fine tuning is sometimes required.

0 Stache 11 months ago in reply to Scillonian

The chain is clearly catching on the second cog. Most ikely causes.

1. Your high limit screw needs adjusting. Most likely fix is a simple adjustment of the high limit screw. Watch one of the sram videos on adjusting the limits of an axs derailleur if this is new to you. Or...

2..You didn't torque the cassette down enough. Those xd cassettes take a ton of torque to fully seat, way more than you would think if you've never used a torque wrench (40Nm or ~354 inlb). I usually don't bother with a torque wrench on my bikes. But, I always use one for cranks and cassettes. It matters here. The small cog will be too close to the frame if this isn't fully seated and you won't be able to adjust the high limit screw without the chain rubbing the frame or catching on the second cog.

3. Derailleur hanger isnt straight. Can't really tell from the video, a shop can't straighten it if you don't have the tool.

4. Gap adjustment could be off but that shouldn't cause your rubbing on the second cog issue. It would cause poor shifts though.

FYI, I usually use a Rival AXS or Force AXS XPLR setup without issue on my 2T