AP Racing Radi-CAL ENP Competition Front Kit 372mm - Subaru WRX, STI

The AP Racing by Essex Radi-CAL Competition Brake Kit with ENP (electroless nickel plated) calipers is a front brake upgrade for the 2015-2021 Subaru WRX and WRX STI. It pairs AP Racing CP9660 Radi-CAL Pro5000R six-piston calipers with 372 x 34mm, 72-vane AP Racing J Hook discs on fully floating aluminum hats, built for track days and competition driving.

Why upgrade

Several pounds of unsprung weight reduction from the car's nose, despite a huge size increase. Each caliper weighs 6.2 lb without pads, against 8.2 lb for the factory caliper. Each two-piece disc weighs 19.1 lb, compared with 21.8 lb for the original 326mm disc. The caliper takes a 18mm thick pad for long life and heat tolerance. The ENP (electroless nickel plated) finish is very durable and easy to clean. Every component is designed to resist the heat of extended track sessions. Pistons are sized to work seamlessly with the OEM master cylinder and ABS. It works with the OEM rear brakes or a matching AP Racing rear kit.

Caliper and disc construction

On the Subaru WRX, STI, the CP9660 caliper mounts radially on a dedicated bracket at 180mm centers with a 42mm offset, with an M10x1.0 inlet thread. The championship-winning 72-vane AP Racing J Hook discs are fully floating. The discs use anti-knockback, anti-rattle attachment hardware. The disc metallurgy is designed for the temperatures seen on track, for a long service life. Spiegler stainless steel brake lines with a clear sheath reduce compliance compared with the OEM rubber lines. The caliper uses a commonly available 18mm thick pad shape. The electroless nickel plated finish resists wear and deterioration, even at high temperatures. Ventilated, domed-back stainless steel pistons keep heat out of the brake fluid for a very firm pedal.

Features

• AP Racing CP9660 six-piston calipers in ENP finish
• 372 x 34mm, 72-vane J Hook discs on floating hats
• 18mm thick brake pads
• Pistons sized for the OEM master cylinder and ABS
• No caliper removal for pad changes

What's Included

• One pair AP Racing CP9660 Radi-CAL Pro5000R six piston calipers in ENP (Electroless Nickel Plated) finish
• One pair 372x34mm AP Racing CP7177, 72 vane, J Hook racing discs, with fully floating 6061 hard anodized aluminum hats, and attachment hardware
• One pair caliper mounting brackets and hardware
• One pair Spiegler Stainless Steel Brake Lines with abrasion resistant coating
• Detailed installation instructions

Brake pads are not included.

Specifications

Video

Fitment notes

This front kit fits the vehicles in the table below, which we confirmed against two sources using US model years. Essex has confirmed clearance with 2018+ Front OE 19 inch wheel and Volk TE37 SL 18x9 +45. Check your wheel with the Essex wheel fitment template before ordering.

Fitment