Surly Singlespeed Cassette Cog
"Our cassette cogs are designed first and foremost for singlespeeding, but being that we’re Surly, we bumped up the versatility a bit. At the base, the cogs are 4.35mm wide, which allows you to stack a few of them up for a simplified multi-speed drivetrain. Use a 9-speed derailleur if you do that.
- Machined from SCM415 Chromoly steel
- Heat-treated and chrome-plated
- Compatible with 6- to 9-speed 3/32" chains
- Available in 13t–22t"
These are our favourite cogs for single-speeding a freehub body.