The Shimano Alfine SG-S7051-8 brings Di2 electronic shifting to an enclosed 8-speed internal gear hub, delivering smooth, precise gear changes without exposed derailleurs or cables. With a 307% gear range and compatibility with Shimano E-bike motor units, it suits urban commuters, tourers, and e-bike builds alike — all in a low-maintenance sealed package.

Highlights

  • 307% total gear range across 8 speeds
  • Shimano Di2 electronic shifting — precise actuation under load
  • Approved for Shimano E-bike and non-E-bike use
  • Centre Lock disc brake interface
  • 36-hole lacing for strong, versatile wheel builds
  • Includes rotor mount cover
  • Sealed internal gear system — minimal maintenance, all-weather reliable
  • Aluminium hub shell construction

Internal Gear Technology

The Alfine S7051-8 uses Shimano's Inter-8 planetary gear system housed in a sealed aluminium shell. The improved internal structure delivers higher shifting performance even under the elevated chain tension produced by E-bike motors, making it a natural fit for assisted commuter and cargo builds. All gear changes happen electronically via Di2, with no mechanical cables to stretch or corrode.

Disc Brake Integration

The hub features a Centre Lock rotor interface and includes a rotor mount cover. A built-in Power Modulator provides easy, progressive braking control. The 135mm over-locknut dimension (O.L.D.) suits standard rear dropout spacing on city, hybrid, and commuter frames.

Compatibility & Fit

  • Over Locknut Dimension (O.L.D.): 135 mm
  • Axle length: 187 mm
  • Spoke holes: 36H
  • Brake mount: Centre Lock (disc)
  • Shifting: Shimano Di2 electronic (requires compatible Di2 junction and battery)
  • E-bike compatible: Yes — approved for Shimano MU-UR500 / MU-UR510 motor units
  • Spoke gauge: 13g (2.3 mm) or 14g (2.0 mm)
  • Colour: Black

Shimano provides a manufacturer's warranty on this product against defects in materials and workmanship. Opening or disassembling the hub, or using non-approved lubricants, will void the warranty. For warranty support, return the item to Tune Cycles.

  • 8-speed internal gear hub with 307% total gear range
  • Shimano Di2 electronic shifting system
  • Approved for Shimano E-bike and non-E-bike use
  • Centre Lock disc brake interface with included rotor mount cover
  • Built-in Power Modulator for smooth, progressive braking
  • 36-hole flange for strong wheel builds
  • O.L.D. 135 mm, axle length 187 mm
  • Sealed aluminium hub shell — all-weather, low-maintenance
  • Compatible with Shimano MU-UR500 / MU-UR510 motor units
  • Black anodised finish
Speeds8
Gear Range307%
Shifting SystemShimano Di2 electronic
Brake TypeCentre Lock disc
Over Locknut Dimension (O.L.D.)135 mm
Axle Length187 mm
Spoke Holes36H
Pitch Circle Diameter92.6 mm
Flange Diameter104.3 mm
Flange Width3.2 mm (left & right)
Flange Distance57.3 mm
Offset3.15 mm
Supported Spoke Gauge13g (2.3 mm) / 14g (2.0 mm)
Hub Shell MaterialAluminium
ColourBlack
E-bike ApprovedYes (MU-UR500 / MU-UR510)
IncludesRotor mount cover
SKU SHM-ISGS70518AL
Barcode # 4524667905370
Brand Shimano
Shipping Weight 0.3000kg
Shipping Cubic 0.001000000m3
Unit Of Measure each
Must be installed and serviced by qualified bicycle mechanic