Surly Singleator

Turn your geared bike into a singlespeed machine with Surly's Singleator. The Singleator mounts to your derailleur hanger and provides a smooth, quiet and adjustable means of tensioning the excess chain slack on any bike. It's made from strong forged steel and features a triple-sealed spring, large-cog capacity, chain guides, fully-adjustable chain line, floating pulley, and a stainless-steel pivot bushing. And, it works with both BMX and standard chains.