Surly Splined Single Speed Cog 3/32"

?Quality single speed cog for Shimano type splined cassette freehub bodies.  These teeth are cut square so work with sprung chain tensioners on single speed conversions.

The base is 4.5mm wide to prevent damage to the free hub splines.

Compatible with all 6-9 speed chains, we recommend the KMC X1 nickel plated 3/32" single speed chain.

Surley say :-

Our cassette-type cogs are designed to fit on standard Shimano compatible freehub bodies. These cogs have a tall tooth profile that is essential for preventing chain skip from the extra torque a singlespeed drivetrain encounters. In addition to being a stellar SS cog, the cog base width (where it contacts the freehub body) is 4.35mm, so you can stack a few of them up and use a 9-speed shifter for a simplified multi-speed drivetrain. This width also prevents it from ruining the freehub body as a result of digging grooves into it like skinny stamped cogs have a tendency to do. Surly cogs are machined from SCM415 CroMoly steel, then heat-treated for toughness and chrome-plated for surface hardening and enhanced chain lubricity. Our cogs will work with 6-9-speed 3/32" chains, although we recommend the inherently updated quality of an 8 or 9 speed chain. They are also available in every increment from 13-22t, so you can select that perfect gear.