Road electronic drivetrain connections

Understanding electronic drivetrain connections

An electronic drivetrain is more than its derailleurs: it needs a power supply, connections and, with Shimano, a complete wired network. This range brings together everything that links the components — and that is often where you’ll find the missing part.

Three systems, three architectures

• Shimano Di2 : wired network E-Tube wired, with a single internal or external battery (SM-BTR1), EW-SD50 or EW-SD300 cables, and EW-RS910 and EW-90A junction boxes.
• SRAM AXS : wireless. Each derailleur has its own interchangeable battery; only the Blips and Blip Box require wiring.
• Campagnolo EPS and WRL : a power unit and internal or external interfaces for EPS; individual batteries for each derailleur with WRL.

Don’t mix up cable generations

• EW-SD50 is used on 11-speed Di2 groupsets and the first 12-speed generations.
• EW-SD300, which is thinner, is used on newer groupsets and fits through narrower cable routes. The two are not interchangeable.
• The lengths vary widely: measure the actual route through the frame before ordering. A cable that’s too short means taking everything apart again.

The small parts that make a difference during installation

• Grommets and cable guides for frame cable exits, port covers for derailleurs, hoods for protection.
• Y-cables such as the EW-JC130, to branch a cable without adding a junction box.
• Battery mounts for the seatpost, notably from Deda, when the frame has no provision for one.
• E-bike connectors EW-JC302 and EW-JC304, for e-bikes equipped with a Di2 drivetrain.

Charging

With Shimano, the battery is charged via the SM-BCR2 and its SM-BCC1 cable, or directly through a port on the derailleur on newer generations. With SRAM, a eTap/AXS charger single charger works with all the batteries, which can be swapped between derailleurs — handy for finishing a ride by switching the two.

To find out more: Why switch to electronic shifting

See also: Road rear derailleurs · Road brake and shift levers · Mountain bike electronic drivetrain parts