From the most well - known brand in automotive performance differentials, comes high performance aftermarket ring and pinion sets for performance enthusiasts. Whether you're looking to improve the performance of your vehicle in day - to - day driving or at the track, Eaton's high performance ring and pinion gear sets complement our differentials, helping you get the power to the ground. Eaton street series ring and pinion gear sets are made in the U.S.A. from high quality 8620 or 4320 steel, which provides long life under daily use conditions.