All of the Chris King bottom bracket offerings use an appropriate Conversion Kit specific to the brand and model of crankset to be used. Conversion Kits are made to account for crank manufacturers' machining tolerances and ensure they mate perfectly with Chris King precision bearings, extending product life, and reducing the potential for noise. CONVERSION KIT #5 For use with ThreadFit T47 30x and T47 30i w/ 30mm crank spindles 68mm, 73mm Bottom Bracket Shells