SHIMANO DURA-ACE TRACK COGSTAYING ON TRACKWhether you're replacing a worn-out cog of just changing your gear ratio, you'll want to use the best parts for your single speed machine. The Shimano Dura-Ace Track Cog is a screw-on track cog for fixed gear bikes. It uses the standard 1. 37" x 24 TPI threads. Features Thread type: 1. 37" X 24 TPIChain Compatibility: 1/8" or 3/32" options available Designed for fixed gear bikes | Shimano | Dura-Ace Track Cog | Black | 14T, 1/8"