Shimano Di2 Wire Types and Compatibility

Types of Di2 Electric Wires and Di2 Generations

Di2 electric wires come in different types depending on the “Di2 compatibility generation.”

Shimano’s Di2 system has compatibility generations based on the “master unit,” which is the control unit of the Di2 system (installed in the battery or battery mount).

There are three generations of Di2, but the Di2 7970 series has electric wires integrated with the junctions, so for practical purposes, there are only two standalone types of electric wires.

For a more detailed explanation of Di2 generations, check out the article below:

SD50 Series

The “SD50 series” electric wires are used in the “Di2 BTR series / DN100 series” systems, which span from the ULTEGRA Di2 6770 series released in 2011 to the GRX RX815 series released in 2019. The wire model is EW-SD50, and it comes in various lengths.

Additionally, this generation includes both external junctions (SM-EW90-A, SM-EW90-B) and an internal junction (EW-RS910) for Junction A. For these setups, Shimano also offers the Y-connector cable (EW-JC130).

Because this generation of Di2 is a fully wired system, it requires connecting the STI levers, Junction A, Junction B, battery, and derailleurs with wires—resulting in the need for a relatively large number of electric wires.

Therefore, you’ll need to plan the wiring carefully and ensure you have the correct number and lengths of electric wires for your setup.

SD300 Series

The SD300 series electric wires were introduced with the DURA-ACE Di2 R9250 and ULTEGRA Di2 R8150 series in 2021, part of the new Di2 DN300 generation. The wire model is EW-SD300.

SD300 connectors and ports are smaller and more compact, and they are not compatible with the previous SD50 series wires.

While there is a conversion adapter (EW-AD305) for Shimano STEPS that connects SD300 to SD50, there is no compatibility between parts from the Di2 BTR/DN100 and DN300 series when it comes to shifting systems.

A major advantage of the DN300 generation is its semi-wireless design, which reduces the number of required electric wires.

However, if you’re using rim brake STI levers, you’ll need to set up the system as a fully wired configuration, similar to the previous generation. In this case, a dedicated Junction B is required, and the number of electric wires needed will be roughly the same as with the SD50 generation.

Shimano Di2 Electric Wire Compatibility

Di2 electric wires use a connector (male) and a port (female) system. Each connection must match the same SD standard (e.g., SD50 or SD300).

Generally, all electric wires have male connectors, while most other components have female ports. If the connector and port are not of the same standard, they will not fit or function.

Shimano Di2 Components and Their Connectors/Ports

Below is a list of each Di2 component series along with its generation and compatible connector/port type:

As of now, only the following three road bike series use the SD300 standard:

1. DURA-ACE Di2 R9250
2. ULTEGRA Di2 R8150
3. 105 R7150

Therefore, unless you’re working with these newer models (excluding the old 7970 series), you can safely assume most Di2 systems are using the SD50 standard.

Also note: if you’re upgrading from SD50-based Di2 components to a newer SD300-based system, you’ll need to replace all of your electric wires as well.