The Shimano STEPS MU-UR500 is the Di2 motor unit that brings electronic, fully automatic shifting to 5-speed internal gear hub e-bikes. Designed for use with the SG-C7050 Nexus internal hub, this compact unit integrates seamlessly into city and urban e-bike systems — eliminating the need for a traditional derailleur and delivering a smoother, more natural ride in stop-start urban conditions.

Highlights

• SYMPHOMATIC automatic shifting: The motor unit reads your cadence and speed in real time, shifting the internal hub automatically so you're always in the right gear without lifting a hand.
• 35% more compact than its predecessor: The MU-UR500 is significantly smaller than the outgoing MU-S705, making it easier to integrate into modern city e-bike frame designs.
• Whisper-quiet operation: Low motor noise keeps the riding experience refined and unobtrusive — ideal for urban commuters who want minimal mechanical intrusion.
• Waterproof construction: A sealed, compact waterproof connector and weather-resistant housing keep the unit reliable in wet Australian conditions.
• E-tube Di2 connectivity: One E-tube port (EW-SD50 compatible) allows integration into the Shimano Di2 wiring network, with firmware updates available via E-tube Project software.
• Part of the Shimano STEPS ecosystem: Designed to work within Shimano's STEPS e-bike platform for city, touring, and comfort riding applications.

How It Works

The MU-UR500 mounts to the internal gear hub and electronically actuates gear changes inside the hub using Di2 signals. In SYMPHOMATIC mode, shifting is fully automatic — the system anticipates the rider's needs based on speed and cadence data from the STEPS drivetrain. Manual override via a Di2 shifter is also supported for riders who prefer control. The single E-tube port connects the unit into the wider Di2 system, including the STEPS drive unit, display, and battery.

Compatibility & Fit

The MU-UR500 (part code IMUUR500C) is specifically designed for the Shimano SG-C7050 5-speed Nexus internal gear hub. It is not interchangeable with 8-speed or 11-speed variants of the MU-UR500. This unit is compatible with Shimano STEPS E5000 and E6100 series e-bike platforms. Connection uses the EW-SD50 E-tube wire (1 port). Firmware updates are managed through E-tube Project software.