Alfine Premium 8-speed Internal Gear Hub.
SG-S501 Model has triple roller clutch design.
Disc brake capability, using Shimano's Center-lock rotors.
Shifting power modulator for smoother shifts
Complete parts kit included.
Shifter w/cable included. Non-turn washers Green & Blue set (for vertical dropouts) Included Note: Comes with 20 tooth standard Nexus sprocket - not the one with