9. Toting around a lot of weight means we will need a lot of stopping power to bring it to a halt. With that in mind, the ProRock 80 gets dual-piston calipers squeezing 13.8-inch-diameter vented rotors. The vented rotors should last longer than solid rotors and will run cooler too. These are the same brakes used on a J8 but the 5-on-51⁄2 bolt pattern was changed to 8-on-61⁄2 inch bolt pattern thanks to a CNC mill. The same mill also opened that center hole up to 43⁄4 inches to fit over the hub.