Performance Machine Spoke Mount Rotor For Harley Touring Performance Machine Spoke Mount rotors are CNC precision ground to guarantee a flat and parallel surface. The rotor is hardened 420 stainless steel and meets Rc36 specifications. A semi-floating design creates a rotor with a greater resistance to wear, warping and rotor deformation. The scallop cut braking surface is drilled in a sweep pattern for ideal heat dissipation while being more lightweight. Features CNC precision machined from 420 Stainless Steel Front dual disc ABS and Non-ABS applications Direct OEM replacement 11.8 x 300mm diameter disc for front left and right applications