Paul Melvin Chain Tensioner Black

Want to build a single speed without having to buy a dedicated frame? Try the Melvin. The Melvin bolts to the frame where the rear derailleur would normally go and allows the use of a single speed rear wheel on bikes with vertical dropouts.

The mounting pivot has spacers that can be arranged to adjust the chainline. In addition, the pulleys have side to side float to quiet slight variances in chainline. The pulleys are made of extruded and machined aluminum and have sealed bearings for durability. They are 2.25mm thick at the tooth which fits inside most narrow 6 through 9 speed chains, and the pulley cage is wide enough to allow 1/8€³ single speed chains as well.

Chain tension is optimized when the chain length is cut so that the pulleys are aligned vertically.