For 1990-2009 cars

In the manufacturing of brake rotors, tolerances of the braking surfaces for flatness, thickness variations and lateral runout are held very closely. Maintain close tolerances on the shape of the braking surfaces in order to prevent roughness in braking performance.

In addition to these tolerances, hold the surface's finish to a specified depth. The maximum rotor surface finish depth is 0.38 mm (0.015 in). The control of the braking surface finish is necessary in order to avoid pulls, erratic performance, and to extend lining life.

Light scoring (depth) of the rotor surfaces not exceeding specifications (which may result from normal use) will not affect brake operation.