The Shimano ALFINE Di2 SG-S7051 brings fully electronic gear shifting to the internal geared hub — delivering a wide 409% gear range with the silent, low-maintenance reliability that ALFINE is renowned for. Whether you're building a clean commuter, a bikepacking rig, or an e-bike urban cruiser, this 11-speed hub keeps your drivetrain weather-sealed and your shifting precise at the touch of a button.

Highlights

• 409% total gear range across 11 speeds — more range than most externally geared drivetrains
• SHIMANO Di2 electronic shifting — instant, precise gear changes with no cable stretch
• Centrelock disc brake rotor mount — compatible with Shimano rotors and adapter rings for 6-bolt use
• 32-hole lacing for a wide range of rim choices
• 135mm over-locknut dimension (O.L.D.) — fits standard rear dropouts
• Bolt-on 10mm axle — secure and simple wheel removal
• Approved for both e-bike and non-e-bike applications
• Available in black or silver

Electronic Intelligence

The SG-S7051 is designed around Shimano's Di2 electronic drivetrain ecosystem. The internal shifting mechanism is actuated electronically, eliminating mechanical cables entirely and delivering consistent, precise shifts regardless of weather or cable wear. The hub uses Shimano's "top normal" shift logic and is wired directly into the Di2 junction and battery system — compatible with S7050 series Di2 components.

Internal Gearing Advantages

All 11 gears are fully enclosed within the hub shell, protecting the mechanism from dirt, mud, water, and debris. The sealed oil-bath lubrication system and labyrinth seals minimise maintenance intervals dramatically compared to an external cassette and derailleur setup. The double roller clutch provides smooth, quiet engagement when under load, and the helical internal sprockets ensure constant gear engagement for efficient power transfer.

Wheel Building

The SG-S7051 features symmetrical 93mm flange diameter on both drive and non-drive sides, with a left flange offset of 29.5mm and right flange offset of 24mm from the hub centreline. Spoke interface is J-bend. The 32-hole drilling suits most performance rim choices for urban and mixed-terrain builds.

Compatibility & Fit

The SG-S7051 requires a Shimano Di2 compatible shift control and junction unit (S7050 series recommended). Rear dropout spacing must be 135mm. Disc rotor mount is Centrelock — use a Shimano CL-to-6-bolt adapter ring if your rotor is 6-bolt standard. Drive-side accepts a single Nexus-compatible cog. Not compatible with cassette freehubs or external derailleur systems. For e-bike builds, confirm compatibility with your specific motor system and Di2 wiring harness.