This particular set of Rock Jock 60s will be fitted with 40-inch tires. As such, the lowest ratio available, 5.38:1, was chosen, sourced from Motive Gear. Both front and rear differentials are high-pinion on this build. High-pinion gear sets were developed for front axle applications. If you need greater strength from your Rock Jock 60 rear axle you can opt for a low-pinion differential. You’ll lose some ground clearance but gain some strength. Need even more strength? Go for Currie’s “Super 60” option which uses a 10-inch ring gear.