My TT/Tri bike no longer automatically shifts the front derailleur

Most Time-Trial or Triathlon bikes nowadays are built using single-button shifters. That's great, but it means that there is no button dedicated to shifting the front derailleur.

These bikes rely on Synchronized Shifting to shift the front derailleur - they automatically shift the front derailleur when the rear derailleur reaches a certain point on the cassette.

Sometimes synchronized shift stops working, and that is likely what you're experiencing here. This can be caused by changing settings in E-Tube Project or updating components, but there are plenty of other possible causes. Doing any of these can cause the bike to switch from either of your synchro shift modes (S1 / S2) back into manual mode.

To restore synchronized shift, double-press the button on the rear derailleur (12-speed bikes) or the main junction (11-speed bikes). The LED will then blink to indicate the selected shift mode.

12-speed Di2 synchro shift LEDs

  • Blue (2 seconds): Manual shift
  • Flashing blue (2 times): Shift mode 1
  • Flashing blue (3 times): Shift mode 2

11-speed Di2 synchro shift LEDs

  • Solid red/green lights: manual shift mode
  • Twice blinking red/green lights: shift mode 1 (default: semi-synchronized shift)
  • Three-times blinking red/green lights: shift mode 2 (default: synchronized shift)

Read more on synchronized shift in my complete guide on Synchronized Shifting.