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AP Racing Radi-CAL big brake kits are the epitome of the "Race on Sunday, Sell on Monday" mentality. In an era of motorsports that sees very little technology making its way to street vehicles, AP Racing has decided to re-write the history books and bring that famous saying back.

After 7 years of success in racing series' such as Formula One, NASCAR, WRC, Formula GP2, Indy, ALMS, Le Mans, and many more, AP Racing decided to bring the World Radi-CAL calipers to the masses. The history behind their Radi-CAL caliper is very interesting. In 2005, they took their latest CAD software and combined it with their latest FEA (finite element analysis) software, and decided to forget everything they knew about them. Their goal was to develop the lightest, strongest, most efficient caliper line possible. The end result is the World Radi-CAL.

By reviewing them in the FEA software, the engineers at AP Racing were able to see that they could create a caliper with more rigidity by removing material in areas where it wasn't structurally beneficial, and add material to areas where the forces were being applied. This is what created the asymmetrical final design. Additionally, by removing the excess material that was not structurally integral to the strength and rigidity of the caliper, they were able to shave off significant weight.

Material Selection

AP Racing race-only calipers are typically constructed out of a piece of billet aluminum that goes through countless hours of machining and preparation. This results in a brake system costing upwards of $30,000.00 USD. This obviously isn't practical for a street vehicle. So the best solution for Radi-Cal street car calipers was pressure forgings. The pressure forging process is considerably more expensive than simple cast calipers, but the savings in weight and the increased durability are well worth the compromise.

Caliper Design

Wanting to bring as much of the technology and experienced gained from the racing version of the Radi-CAL calipers to the street, AP Racing immediately started with a blank sheet of paper and quickly filled in the key points:

  • Weight Savings
  • Strength
  • Design
  • Functionality

Weight Savings

By removing material where it isn't necessary and keeping the material only where it's actually required, AP Racing is able to remove a considerable amount of weight. Additionally, in choosing a pressure forged aluminum manufacturing process, the caliper is 20% lighter than if it were to be constructed out of cast aluminum.


By using a pressure forged aluminum manufacturing process, the caliper is 25% stiffer than if it were to be constructed out of cast aluminum. Additionally, it is designed to only have material in key structurally integral areas so as to better manage the loads being placed on them during hard braking.


AP Racing wanted to build a caliper that wasn't just technically ahead of the competition, but also cosmetically. They've accomplished this by designing one that is hands down the best looking caliper in the big brake kit market.


At the end of the day, AP Racing is an engineering company. They are very talented engineers who eat, sleep, breath, and live high performance. They didn't want to simply build a good looking caliper that would work well for the street- they wanted to build the best looking caliper that would outperform every other caliper in any environment it was in. To accomplish this, they paid close attention to detail, including how easy it is to change brake pads. With the pressure forged removable bridge "H" support, changes take a matter of minutes instead of hours like other big brake kits. The internal seals are rated for supercars like the Bugatti Veyron and McLaren MP4-12C where the cars are put through extreme driving and will undoubtedly see extensive high performance track use.


  • (2) AP Racing 14.5'' 2-Piece Brake Rotors
  • (2) AP Racing 6-Piston Brake Calipers
  • (1) Goodridge Stainless Steel Brake Line Set
  • (1) High Performance Brake Pad Set
  • (2) Mounting Brackets + Hardware

We also recommend the use of Motul RB600 or Motul RBF660 brake fluid (not included) on all vehicles equippedn with larger brakes, or driven in an agressive manner often.


  • 2014+ Infiniti Q50 Sedan
  • 2017+ Infiniti Q60 Coupe

Customers looking for upgrade components for factory Sport Akebono equipped brakes should see our own Z1 2-Piece Rotors and Carbotech Brake Pads.

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