How to connect your Di2 system to your Windows computer

Published September 8, 2019 by BetterShifting, Last updated September 1, 2021

Modern Di2 is basically a couple of controllers and servo motors that communicate with each other using the EW-SD50 wires. Shimano lets end-users configure their own Di2 systems using their e-tube project software. This page explains how to connect your bike to your computer.

Requirements - Road/MTB/GRX/Urban vs E-Bike

Connecting a Di2 bike to a Windows computer is done via the charging/interface port on the Junction A.

Modern road bikes, mountain bikes, and gravel bikes will all have this junction and the required interface/charge port. Some urban bikes will too.

However, STEPS E-bikes or E-MTBs generally use a display without this port. Also, most E-bikes use larger, external batteries and they do not come with the SM-BCR2 charger. If your bike is one of these I'm afraid you're out of luck - you can only connect your bike to a Windows computer using the SM-PCE1/SM-PCE02 diagnostics device.

Older road bikes with external batteries and the SM-EW67A junction can only be connected using the SM-PCE1/SM-PCE02 diagnostics device.

Locate the charging / interace port

You probably know where the charging port is - but just in case you don't, have a look at this image:

Di2 charge and interface port

Make sure you have either the SM-PCE1/SM-PCE02 diagnostics device or the SM-BCR2 charger. Also, download an up to date version of the E-Tube Project software.

IMPORTANT: E-Tube Professional

Note: E-Tube Project Professional does not work with the SM-BCR2 charger. You need to use E-Tube Project 3.4.5 or 4.0.4. Read the Faq page on this for more information.

The older E-Tube Project versions can be downloaded from the E-Tube Project archive.

Connect instructions E-Tube

Connect using e-Tube Project

Plug your charger into the junction box and connect the other end to your computer – the order doesn’t really matter, but I tend to plug the connector into the bike first. Start the e-Tube Project software. Then just click the 'Next' button.

E-Tube Project connect

If you haven't already, the software will tell you to connect your SM-PCE1/02 or SM-BCR2.

It’ll then tell you that charging has stopped because you’ve connected the bike to the computer and started the software.

E-Tube charging stopped

Also, it will tell you to use the disconnect button when you're done and then start unit recognition.

E-Tube for Windows connecting

When the connection has been made successfully you will be shown the Customize tab. This is where you can set up or tweak each component.

E-Tube Project customise screen

Cannot connect using the SM-BCR2? Need to update it?

When Shimano released E-Tube Project 4 they also introduced a lot of bugs. One of those actually prevents you from connecting to your bike using the SM-BCR2.

E-Tube Project displays a message, but won't actually update the SM-BCR2:

SM-BCR2 recognition. The process is interrupted because the version of SM-BCR2's firmware is old. Connect to the Internet and download the latest version of the firmware.

Now.. the workaround is relatively simple, if not a bit frustrating.

You need to download E-Tube Project 3.4.5 and update the SM-BCR2 that way. After that it's safe to use E-Tube Project 4.

E-Tube Project 3.4.5 can be found on the Shimano E-Tube Project site, or through this direct download link.

View installed components

Sometimes it is useful to see the list of installed components. When troubleshooting unresponsive components for example. By checking the list of installed and connected components you can figure out what part of the Di2 "circuit" is broken. Almost all components are listed on the Update tab.

E-Tube Project Update Firmware

If a component isn't listed here that means that it either isn't connected or it doesn't have any firmware that can be updated. Junction B (SM-JC41 / SM-JC40) and the external battery won't show up here for example.

Done? Use the disconnect button

When you're done please use the disconnect button as seen at the top left of the window. If you do not, the bike may not respond or may end up draining the system battery until you reconnect it. It isn't hard, but it is something to keep in mind.

Other things you can do with E-Tube Project:

Questions? Leave a comment or send me a message.