Garmin bike computers frequently disconnect from SRAM AXS rear derailleur

Tech Tech Help
1

My current setup:

  • MY24 Santa Cruz Stigmata size XL
  • SRAM X0 Eagle Transmission rear derailleur
  • SRAM Red E1 shifters. The left bonus button is configured to go to previous page on the Garmin with single press while the right button tells the Garmin to go to the next page.
  • Garmin Edge 1040 Solar mounted on a RouteWerks handlebar bag (or Edge 840 mounted on an out front mount when I’m racing)

Very often during my ride, I will see the “shifting connected” message popping up on the bike computer. This is an indication that at some point, the bike computer had disconnected from the rear derailleur. The bonus button on the shifters - usually the left shifter but sometimes the right shifter as well - also very often fail to control the bike computer, another indication of the connectivity issue between the rear derailleur and the bike computer.

My understanding is the shifters connect indirectly to the bike computer via the rear derailleur. The Red E1 shifters communicate via a proprietary wireless protocol with the rear derailleur, and the rear derailleur uses the ANT+ protocol to talk to the bike computer. It is this ANT+ communication between the rear derailleur and the shifters that is problematic in my setup. This issue does not affect just the SRAM X0 Eagle Transmission rear derailleur. I also had similar issue with SRAM Force XPLR rear derailleur.

Short of moving the bike computer closer to the rear derailleur, can anyone think of a way to improve the connectivity between the rear derailleur and the bike computer?

1 Like
2

I have the same problem with a Force XPLR rear and Edge 840 but have been able to confirm that it’s exactly the same with a Wahoo ELEMNT, so it’s not likely to be the 840 or its position (I tried the Garmin in a jersey pocket and no improvement). No bonus buttons but the “shifting connected” message keeps appearing and the gear display jumps from being clearly wrong to being correct. So frequent that it’s unusable.

My case is complicated by the fact it’s on a Trek Domane+ which uses the TQ e-bike system, and there seems to be an interaction with that, whereby with no assistance selected the signal seems solid, but as soon as I select assistance from the motor this problem you describe pops up every time.

Has anyone else experienced this, or even better, found a fix?

3

Just curious, how did you know this issue was occurring when you had the Garmin in the jersey pocket?

4

Ah, a good question. From memory I think the gear ratios are saved in the FIT file and it was clear when it was dropping out.