We created the fitment conversion kit so you can upgrade your stock Harley-Davidson cartridge-equipped fork to a FOX GRIP-Street Performance 41mm fork cartridge kit. The fitment conversion kit is a bolt-in solution that doesn't require additional modifications to your fork. Simply swap out the OE cartridge with FOX and experience improved handling. Attack the corners with a new sense of comfort and control. Use this FOX fitment negative spring and bottom-out cup conversion kit in addition to the FOX GRIP-Street Performance 41mm fork cartridge kit.