Description: Dual Rear Wheels. Drive Ratio 3.73. Drive Ratio 4.10. Most GM OE brake rotors sold in the U S are Ferritic Nitro-Carburized, or FNC rotor These rotors typically last two times longer, compared to non-FNC rotors, due to improved pad wear behavior OE brake components are specifically designed to work with your GM vehicle safety systems This GM Genuine Part is designed, engineered, and tested to rigorous standards and is backed by General Motors