Wilwood 160-9960 12.88" Left, Slotted, 0.81" Thick, 12 x 8.75 Bolt Pattern, 48-Vane, GT Replacement Rotor | GT curved vane rotors are built for the extreme conditions of professional motorsports. The superior heat absorption and dissipation characteristics of these heavy wall directional vane rotors are the keys to preventing heat fade and realizing long service life from the rotors and pads. All rotors are cast from premium grade, long grain carbon iron for long wear, thermal stability, and resistance to distortion. Every GT rotor is fully detail machined to eliminate stress points and unnecessary weight away from the pad sweep face. The faces and O.D. are precision turned to less than .001" for flatness, parallelism, and run-out. Accesspeed has found that the asymmetrical face slot pattern provides smoother engagement through reduced harmonics and improved thermal balance between the I.D. and O.D. of the rotor. Every rotor is then individually dynamic balanced to provide vibration free performance at any speed. These rotors provide the highest cooling capacity and longest service life for extreme braking short tracks and road course competition.