AP Racing Competition Big Brake Kit Subaru Impreza WRX STI

AP Racing's Heavy Duty J Hook Racing Discs were specifically designed to handle racetrack abuse. These are the same discs used on the fastest cars at the elite level of motorsports, including ALMS, NASCAR Sprint Cup, etc. They provide increased cooling, less judder, fewer cracks, and an increased service life vs. competing discs. When you run an AP disc, you can be confident that you're using the best parts available at any price point.

Most aftermarket discs have 30 to 48 vanes. Many times those vanes are straight, or non-directional, with a sub-optimal amount of space between disc faces. After extensive CFD and thermal stress analysis, AP designed the Heavy Duty J Hook with 70 vanes and a wide 16.5mm air gap to increase airspeed and heat transfer, while reducing deflection and remaining reasonably lightweight.

The increased directional vane count on the J Hook Heavy Duty Disc amplifies air speed through the disc, reduces air recirculation between vents, and also increases convective heat transfer and heat distribution. In other words, both air and heat move more quickly and evenly through the disc, creating increased stability under the extreme loads of racetrack use. The disc is less prone to coning, distortion, and cracking, while providing cooler running temperatures, less brake fade, reduced judder, and a longer service life.