... motor,high powerfull 2.high efficiency, low nosie electric bicycle brushless dc motor,electric bike hub motor,e-bike motorBrushless Hub ... 5cm Min. Fork Width Requirement: Min.13.5cm Corresponding Controller: 48V 500W Controller Available Speed Gear Quantity: Single Speed, 5-Speed, ... , 6-Speed Available Wheel Size: 16", 18", 20" electric bicycle brushless dc motor,electric bike hub motor,e-bike motor