1961-68 Cadillac Big Brake kit. The 13” front system uses 13” cross-drilled, gas slotted and zinc washed rotors, mounted to 2024 T6 billet aluminum CNC machined anodized hubs and PBR C15 calipers that attach to the spindles with custom caliper mounting brackets. PBR C15 calipers have twin 52mm pistons and a larger brake pad surface area that offers about 60% more stopping power in the caliper than the popular C5 caliper at half the cost. Big Brake kits require larger diameter disc brake type wheels: our 13” kit requires 17” wheels.