Axle conversion kits are required for converting your current hub to be used on various other axle platforms. Fits Chris King R45D front hubs with serial numbers starting with 641 (6 Bolt) or 661 (Centerlock) If converting from QR to TA, an adjusting clamp will also be required PHB653 / PHB653B 100mm x 12mm Thru-axle If converting from TA to QR, the axle, axle end, and adjusting cone will be required PHB652(B) 100mm x 9mm QR PHB651(B) QR front axle end for R45D PHB725(B) Front adjusting cone for R45/R45D