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 our precision bearings, extending product life, and reducing the potential for noise. CONVERSION KIT #4 For use with Press Fit 30 and ThreadFit T47 30i 68mm Wide Bottom Bracket Shells 24mm to 22mm Stepped Mountain Cranksets Common Cranks: SRAM mountain, Bontrager mountain, TruVativ mountain, Zinn mountain Note: this item is no longer in production.