Paul Component Engineering Melvin Chain Tensioner SilverPaul Component Engineering Melvin Chain Tensioner Silver. Paul Components Melvin Chain Tensioner. Converts frames for single speed use. Long enough for a Dingle setup (2 rings one cog) 20T max. The Melvin uses two pulleys just like a rear derailleur which gives it 20 teeth of chain wrap Will work with multiple front chain rings while maintaining proper chain tension The pulleys are made of extruded and machined aluminum and have sealed bearings for