C5/C6 Corvette SCCA T1 Hardbar, Replacement Competition AP Racing Brake Rotor / Disc Ring

AP Racing 12.81" x1.25" (325mm x 32mm) Heavy Duty, 70 Vane, J Hook Racing Brake Disc (Left or Right Side, Directional Vanes)

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.

Feature: Exclusive AP Racing J Hook slot pattern
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When you cut a slot or drill a hole in a disc you impact heat transfer. The area around the slot or hole acts as a cool spot when the disc heats up, which is not ideal. Ideally, heat is distributed uniformly around the disc so it can be hit with the cooling air that is pumping through the disc, radiate outwards away from the disc, etc. Cool spots create stress risers and increase the likelihood of the disc cracking. They also cause the face of the disc to distort unevenly, leading to uneven pad deposits, vibration, and judder.
Benefits
During exhaustive R&D testing, AP's J Hook design was found to create a constant pathway of evenly distorted material on the face of the disc. The hooks are spaced out as evenly as possible both around the circumference of the disc, as well as from the inside edge (where the hat attaches) to outer edge, with a slight overlap to promote even heat distribution/distortion. In addition to reducing cracking, the even heating of the disc also helps provide an even transfer layer of pad material on the disc when you bed them in.
Additionally, the J Hook slot pattern produces a greater number of leading edges for the pads to bite into vs. a traditional curved slot pattern. While this may lead to slightly more whirring or scraping noises from the discs when applying the brakes, the benefits of more even heat distribution, less propensity to crack, cleaner pad material transfer during bed-in, and more bite far outweigh the slight increase in NVH for the serious enthusiast.

AP Racing has been designing brake components for more than 50 years.  They've had their components on cars that have won more than 600 grand prix's (Formula 1).  On any given race weekend, AP J Hook discs can be found on 75% or more of the NASCAR Sprint Cup grid.  AP has learned from these experiences, and have developed a proprietary iron alloy with extreme durability, designed specifically for what you intend to do with it (flog the hell out of it). 

Elite level teams choose AP Racing because they know the work has been done to provide the best available product at any price level.  The AP Heavy Duty J Hook is a direct derivative of AP's vast racing experience.  You can buy with confidence knowing that you're getting the best product available at any price point.  A note of caution however: the J Hook design is often imitated, and there are a number of lesser quality imitations on market.  Before purchasing, make sure you are getting an authentic AP Racing J Hook!