Shimano SD300/SD50 Di2 cable adapter EW-AD305 - IEWAD305

The EW-AD305Shimano r (ref. IEWAD305) is a connection adapter for Di2 and Shimano STEPS systems, designed to ensure compatibility between two generations of electronic cables: EW-SD300 (new generation) and EW-SD50 (previous generation). It allows recent Shimano components to be connected to peripherals or tools that still use the old standard, without altering the rest of the cabling.

What is the EW-AD305 used for?

This adapter acts as a ‘bridge’ between two E-Tube connector formats:

• EW-SD300 → SD50
• Enables the interconnection of hybrid Di2 components (older and newer models)
• Used in 12V Di2 road bike set-ups, electric mountain bikes and STEPS- Shimano systems

In practice, it is often used to:

• Mixing R9200/R8100-generation Di2 components with older peripherals
• Connecting diagnostic tools or units that still require SD50
• Adapting Shimano STEPS e-bike set-ups (EP8, E6100, etc.)

How it works

• On one side: EW-SD300 connector (thin, 3.45 mm)
• On the other: EW-SD50 connector (wider, 5.1 mm)
• Data and power transmission via the E-Tube protocol Shimano
• Waterproof and secure connection, designed for road and off-road use

Key features

• Compatibility between Di2 generations (SD300 ↔ SD50)
• Essential for certain hybrid set-ups or upgrades
• Simple ‘plug & play’ installation
• Reliable, moisture-resistant connection
• Shimano -approved part (part no. IEWAD305)

FAQ

Is this compulsory on a 12-speed Di2 bike?

No. On a brand-new setup (R9200 / R8100 with SD300 cabling), it is generally not necessary.

Can it be used for a Di2 upgrade?

Yes, especially if you’re mixing older components (SD50) with newer ones (SD300).

Is it compatible with Shimano STEPS?

Yes, it is often used on Shimano e-bike systems (EP8, E6100) to ensure compatibility between generations.

Does it improve performance?

No, it does not affect performance. It serves solely as a compatibility interface.