How to Change Shimano Di2 Synchronized Shift Modes

Written by : Mr Mamil
Last updated :

The Synchronized Shift function was released back in June 2016 when Shimano launched the Dura Ace R9150 series. It wasn’t a new technology at launch. The same technology was already in use in the mountain bike XTR and XT Di2 groupsets prior.

What is Synchronized Shift?

Synchronized Shift is a function that automatically shifts the front derailleur when the rear derailleur is shifted, allowing the derailleurs to work together efficiently.


What are the advantages of Synchronized Shift?

The main advantage is time-saving when shifting the front chainring. With the synchronized shift, the shift only happens once (semi-synchronized) or automatically (fully-synchronized), which saves time, especially during races.

Compared to manual shifts, one would need to shift the front and then the rear to find the ideal gear ratio to maintain the cadence. Synchronized shifting eliminates the need for double shifts.

Shimano Di2 shift modes

There are three shift modes to choose from.

  1. Manual. The front and rear derailleurs shift independently, just like mechanical shifting.
  2. Semi-synchronized. The rear derailleur automatically shifts up to 4 cogs (default is 2) when the front chainring goes from big to small or vice versa. This ensures that the gear ratio remains similar when shifting the front chainring by compensating the rear.
  3. Fully-synchronized. The front derailleur automatically shifts up/down when the rear derailleur shifts. The shift points (cog size) are programmable in the E-tube app to trigger the front shift. In other words, it’s like riding a 1X bike, as there’s no need to shift the front derailleur.

How to select Shimano shift modes?

You can select the shift modes either by pressing the function button or using the E-tube app via Bluetooth connectivity or E-tube Project software on the computer.

The steps below will cover the steps using the function button.

For 11-speed Shimano Di2

Shimano Di2 Junction A Functions

Select the shift modes by double-pressing the function button on Junction A. Double-press again to cycle through the shift modes.

The selected shift mode is indicated by the LED’s.

  • Manual : 2 seconds red, 2 seconds green
  • Semi-synchronized : 2 times red blink, 2 times green blink
  • Fully-synchronized : 3 times red blink, 3 times green blink

For 12-speed Shimano Di2

Shimano Dura Ace R9250 Rear Derailleur Diagram
Photo : Shimano

Select the shift modes by double-pressing the function button on the rear derailleur. Double-press again to cycle through the shift modes.

The selected shift mode is indicated by the LED’s.

  • Manual : Blue (2 seconds)
  • Semi-synchronized : Flashing blue (twice)
  • Fully-synchronized : Flashing blue (thrice)

What are the requirements for Synchronized Shifting?

Synchronized Shifting is available for 11 and 12-speed Shimano Di2 groupsets;

  • Dura Ace R9250
  • Dura Ace R9150
  • Dura Ace R9000
  • Ultegra R8100
  • Ultegra R8050
  • Ultegra R6870

In addition, you’ll need to have at least the BT-DN110 battery or the BM-DN100 external battery mount.

Is Synchronized Shift available for 10-speed Shimano Di2?

Synchronized shifting is not available for 10-speed Shimano Di2, as the technology was released after this groupset was launched.

Which shift mode is the most widely used?

From my experience and observation, the semi-synchro is preferred by most cyclists. It has the best of both worlds; time-saving and control over the front shifts.

I’m not a fan of fully synchronized shifts, as there’s a risk of unexpected front shifts.

Manual shifts are fine, but you’re not using the Shimano Di2 to its fullest potential.

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