Product Description Shimano Alfine crankset FC-S501 - with chain guard on both sides for your City bike The Shimano Alfine FC-S501 crankset comes with a chainring (39 or 42 tooth) and two chain guards, which are mounted inside and outside. Whether silver or black - it looks simply great on city bikes and touring bikes with 8- or 11-speed internally geared hubs. The 5-arm aluminium crank with 130 mm bolt circle diameter features the 2-Piece Design, which optimises the stiffness as well as power conversion. Specifications:Application:City, City & TouringChainring Mount:130 mm bolt circle diameter, 5-armTechnical Information:Series:Alfine S500Crank Arm Material:aluminiumChainring Material:aluminiumGradation:39 or 42 toothCrank Arm Length:170.0 mmChainline:49.2 mmAxle Diameter:24 mmCompatible BSA Shell Width:68 mmBottom Bracket:BB-RS501 Hollowtech IIRecommended Chain:HG 9-speed (super narrow, CN-HG93, CN-HG53) or HG 8-speed (1/2" x 3/32" ; CN-HG71)Compatibility:Internally Geared Hubs:Alfine 8-speed, Alfine 11-speed, Nexus 7-speed, Nexus 8-speed, Nexus 3-speed 3DSprocket:CS-S500Chain Tensioner:CT-S500Chain Case:not compatibleFeatures:crank arms anodised and painted, chainring anodisedchain guard (outside and inside) made of anodised aluminiumdiameter of bash guards: 174 mm (39 T) or 190 mm (42 T)Technology:2-Piece Crankset With the 2-piece designed cranks from Shimano, the right crank arm is precisely matched to the interaction with the bottom bracket. This increases the stiffness and keeps the weight low. Further spaced bearings also improve strength and contribute to more pedalling efficiency. The precision manufacturing of the bearings ensures easy installation and low maintenance. 2-Piece cranks share a 24mm axle diameter with Hollowtech II cranks, so they are also compatible with Hollowtech II bottom brackets. Manufacturer Numbers:black 39 tooth:E-FCS501CA9C2Lblack 42 tooth:E-FCS501CB2C2Lsilver 39 tooth:E-FCS501CA9C2Ssilver 42 tooth:E-FCS501CB2C2SContents:1 x Shimano Alfine FC-S501 crankset (39 or 42-tooth)2 x Shimano chain guard1 x Shimano BB-RS501 bottom bracket1 x crank bolt1 x spacers Manufacturer: Shimano Europe B.V. High Tech Campus 92 5656 AG Eindhoven Netherlands info@shimano-eu.com