The Trail-Creeper ring & pinion gears are tested and proven on trails all over the world. The Trail-Creeper ring & pinion are constructed from 8620 steel and heat treated for maximum durability and service life. Trail Gear's engineers utilize Gleason gear-cutting technology to provide the most precise cut on the gear teeth, allow for better torque, power transfer & fuel efficiency. The Gleason gear-cutting technology also greatly reduces running noise, so you can install these gears in your daily driver and not worry about the annoying drone that many gears swaps create. These ring and pinion sets are designed for rear axles only.