AP Racing 325x32mm J-Hook Competition Brake Discs (L and R Front)

The AP 325mm J-hook rotor rings that are supplied with this kit directly come from AP’s motorsports line of iron brake discs. The J-Hook slot pattern is AP’s latest, most aggressive slot pattern available. These discs are similar to the discs being purchased by the top teams in various motorsports categories around the world.
AP Racing's Heavy Duty J Hook Racing Discs are specifically designed to handle race abuse. 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.”

AP3908 J-Hook Rotor Specs & Benefits:

• Industry/competition race standard rotors
• 70 directional vanes heavy duty design, 16.5mm air gap
• True floating rotor design to allow axial float and radial heat expansion of the disc
• Floating rotor also reduces stress and fatigue on the brake hats
• Components in this kit are from AP’s competition product line (these are NOT “street” components)
• 50 years of brake engineering experience are in these rotors and calipers
• AP J Hook discs can be found on 75% or more of the NASCAR Sprint Cup grid, and AP components are supplied to most top teams in Grand-Am, ALMS, BTCC, WTCC, and Super GT.
• AP’s proprietary gray iron alloy with extreme temperature and wear durability
• AP’s exclusive J Hook design to promote even heat distribution and reducing cracking, as well as increased leading edge surface area for increased initial “bite” compared to standard slotted rotors.
• Longer service life means less time and money spent swapping rotor rings.