Problem Solvers Singlespeed Cog 21t fits Problem Solvers Carrier 6-bolt hubs

Problem Solvers Singlespeed Cog 21t fits Problem Solvers Carrier or 6-bolt hubs. Problem Solvers Singlespeed 6-bolt Cogs are designed to be used with the Problem Solvers Cog Carrier.

Compatible with 3/32" and 1/8" chains

Cog is also 6-bolt rotor mount compatible for fixed gear use (see instructions for applicable warnings)