Folks wanting to perform a singlespeed conversion start by taking off the gears in favor of one cog…but the work isn’t done there. On a multi-speed bikes with vertical dropouts, the derailleur serves not only to change the gears, but also keep the chain tight on the front chainrings, preventing it from falling off (most of the time). Our Two-pulley Chain Tensioner replaces the function of the derailleur—keeping tension on the chain—but also adjusts left to right, to line up perfectly with the singlespeed cog.
This is not only handy for singlespeed hubs, but also for internally geared hubs—in both cases chain tension and chain line are important. Our resident Problem Solvers engineer and all-around bike hacker Dutch-E went one step further, using a front derailleur and two chainrings to create a 2 x 1 cog setup. The Two Pulley Chain Tensioner allows the front derailleur to shift between the front rings, but keeps the chain directed at the single rear cog. This is affectionately referred to as a “Dinglespeed” the combination of that with an 8-speed gives him a mega gear range…but that is a whole ‘nuther topic in itself.