This simple to install conversion kit upgrades your stopping power by up to 20% The existing 160mm rotor will convert into a 180mm full circle type brake disc with this kit. As mountain bike discs use a 6 bolt standard centre hub internationally, you have a choice of either upgrading to a contour rotor or full circle. An international bolt spaced standard relocation bracket is included to aid in repositioning stock calipers in alignment with new oversize rotor.