“Radi-CAL” is a blanket term used to describe AP Racing’s patented asymmetrical brake caliper design. Radi-Cal technology is grounded in Computer Aided Design (CAD) and Finite Element Analysis (FEA), and allows for organic, alien-looking designs that are a radical departure from conventional caliper designs of the past. Calipers leveraging the Radi-CAL design philosophy are widely considered the pinnacle of current brake caliper technology. Since their inception in 2007, these revolutionary calipers have amassed a lengthy string of race victories at all levels of professional motorsport, while redefining brake performance expectations. Please click here for the AP Racing Radi-CAL story.

While our standard Essex Designed AP Racing Competition Brake Kits remain an excellent choice for chasing lap times, our Radi-CAL Competition Brake Kits bring the bleeding edge of racing brake technology to the common enthusiast. These systems include all of the standard features of our Competition BBK's, but leverage AP Racing's Pro5000R Radi-CAL's to increase stiffness, lower mass, and optimize cooling and wheel fitment.

The key benefits of the Radi-CAL design are:

• Massive Stiffness Increase- A 30+ % increase in both static and dynamic stiffness allows for far less deflection under load, which means superior pedal feel & modulation, more even pad wear, and longer caliper service life.
• Considerable Mass Reduction- Removing all extraneous caliper mass lowers the caliper weight, despite the huge stiffness increases.
• Optimized Airflow- Air moves around and through the caliper more efficiently, providing superior heat evacuation.
• Efficient Packaging- The wide, asymmetric caliper profile and internal porting allows the caliper to fit into tighter spaces.

ENP (Electroless Nickel Plated) Finish

In the past, AP Racing had reserved their ENP finish exclusively for professional race teams. Starting in late 2022, we are thrilled to now offer the ENP finish to our club race, time trial, and HPDE customers! The first obvious weakness when looking at a typical aftermarket caliper is the finish. Most aftermarket calipers come in a painted finish, whether they are red, black, or gold. That painted finish is designed to look pretty and prevent corrosion in harsh winter environment. Unfortunately, for all of the compliments painted calipers generate, there is an associated price if you drive the car in a track environment. That price is the chipping, flaking, fading, color shift, and general degradation of that finish in a fairly short period of time. Some OEM calipers can go from the as-delivered color to a nasty shade of brown in as little as one weekend. While this is typically worn as a badge of honor among our more hardcore customers, let’s face it…they still look terrible. More importantly however, all of those bits of paint end up in places they’re not supposed to, which we’ll get to in a minute.

Why does this happen? Heat. Paint and powder coat cannot adequately handle track temperatures. Powder coat also has some notorious issues with shrinkage. The powder coat layer expands and grows when the caliper is heated. When it cools, the powder coat doesn’t necessarily shrink in step with the caliper body itself. What’s left is a loose shell of finish hanging limply on the caliper body. That shell then cracks and falls to pieces.

Paint can also have similar issues depending on how it is applied. If you were to line up a few aftermarket calipers from the same manufacturer, you would likely see that the painted finish on each of those calipers is slightly different. Some have a thicker coat, some thinner, slightly different shades of red, etc. Painting is to some extent an art form, and must be performed in a tightly controlled environment. If it isn’t, you’re always going to see variation. A thick coat makes the part look soft around the edges, and is prone to cracking off in the same manner as the powder coat described above, leaving the underlying finish exposed. A part without enough paint will look uneven, and will not protect the underlying aluminum particularly well either. In addition to problems with cracking, flaking, and uneven application, paint and powder coat also experience extreme color shift when heated. Red becomes maroon or black, gold becomes brown, and black just gets uglier.

The calipers we use in our AP Racing by Essex Radi-CAL Competition Kits don't have any of the above issues. In this kit, the calipers feature an Electroless Nickel Plated (ENP) finish. Because ENP is extremely hard and resistant to wear and corrosion, it is used in applications as diverse as the manufacture of hard disc drives and the targeting pods of the F-15 Eagle fighter jet. ENP is perfect for calipers that are frequently bled, and it won't chip and flake like a painted caliper if you bump it with your box wrench. It is the ideal finish for highly complex parts like the AP Radi-CAL, because it can be applied to the caliper's many curves and pockets in a very thin, uniform manner. ENP also has extremely low porosity, which is perfect for components exposed to harsh chemicals such a brake fluid. If you do get fluid, dirt, or debris on your calipers, ENP is incredibly easy to clean, and a quick wipe will bring it back to its former luster. Last but not least, ENP provides a jewel-like, liquid metal appearance to your brake system. The neutral, yet eye-catching finish meshes perfectly with just about any color scheme as it catches and reflects light.