NEW Surly Cogs Track Cog Surly Track Cog 3/32'' X 17t Silver type_protective-pads-armor Axle Diameter (mm): 12

Axle Diameter (mm): 12

Rear Derailleur: Shimano GRX RD-RX812 Rear Derailleur - 11-Speed

Chainguide Orbea Rise chainguide

Shimano Alivio M415 7/8-Speed Chainrings

Front and rear rack mounts

NEW Surly Cogs Track Cog Surly Track Cog 3/32'' X 17t Silver type_protective-pads-armor Axle Diameter (mm): 12Surly track cogs are threaded the same as a BMX freewheel (1. 375 x 24 tpi right hand threads). This means that they will fit on single speed rear hubs, as well as BMX freewheel hubs, but this application is not recommended. Track cogs are meant to work on track hubs only. 415 hardened chromoly steel 1. 375" x 24 tpi Photo for color and material reference only Tooth Count: 17