Shimano Di2#

Di2 (Digital Integrated Intelligence) is Shimano’s electronic shifting platform. Mechanical shift cables are replaced entirely by electric motors in the derailleurs, a rechargeable battery, and a wired E-TUBE network connecting all components. Shift buttons send electrical signals; the derailleur motors execute the shift precisely and repeatably with no cable stretch, friction, or adjustment drift.

First introduced in 2009 (Dura-Ace 7970), Di2 is now available across Shimano’s road, gravel, and MTB groupset families. Current generation: 12-speed (introduced 2021–2022).

In This Setup#

• Shimano GRX Di2 — installed on the Canyon Grizl CF 8 Di2 as a mixed GRX/XT 1×12 configuration

System Architecture#

A Di2 system has four layers:

Shift levers / buttons
        │  E-TUBE wire
Junction box (A2 / B1)
        │  E-TUBE wire
Derailleurs (motors)
        │  E-TUBE wire
Battery

All components communicate over the E-TUBE proprietary wired bus. The junction box is the hub — it routes signals between levers, derailleurs, and battery, and provides the port for charging and firmware updates.

Key Components#

D-Fly Wireless Module#

The optional D-Fly module (EW-WU111 for 12-speed; EW-WU101 for 11-speed) connects to the E-TUBE network and broadcasts system data wirelessly:

This is what allows a Garmin or Wahoo head unit to display current gear and Di2 battery status on-screen and log the data to a .fit file.

E-TUBE Project App#

Shimano’s companion app (iOS / Android / Windows) connects via Bluetooth LE to a D-Fly module or wired via USB to the junction box charging port.

Groupset Families#

Road#

Gravel#

MTB#

Battery Life & Charging#

Battery life varies by groupset, riding conditions, and shift frequency. Typical figures for a 12-speed internal battery:

The system displays a low-battery warning on paired head units when charge drops below ~25%. Charging is via standard USB-C (12-speed) or micro-USB (11-speed) at the junction box port.

Advantages Over Mechanical Shifting#