KSport ProComp Rear Big Brake Kit

2008–2015 Scion xB (xB2)

BKSC040-432SO

Overview:

The KSport ProComp 13" 4-Piston Rear Big Brake Kit is engineered specifically for the 2008 to 2015 Scion xB (xB2) model, delivering a significant upgrade in braking performance and reliability. Designed for enthusiasts seeking enhanced stopping power and improved brake feel, this kit integrates advanced brake technology to reduce fade and maintain consistent pad contact during aggressive driving or spirited street use.

Whether upgrading for daily driving confidence or occasional track use, the ProComp rear big brake kit offers a balanced solution that improves safety and control without compromising vehicle dynamics.

Key Features:

This big brake kit combines innovative design with high-quality materials to provide superior braking performance. Key features include:

• 4-piston aluminum calipers machined from aircraft-grade billet for strength and lightweight performance
• 13-inch (330mm) large ventilated rotors designed to dissipate heat efficiently and reduce brake fade
• Differential bore caliper design that enhances pad wear uniformity and caliper rigidity
• Stainless steel braided brake lines to eliminate expansion under pressure, improving pedal feel and response
• Machined aluminum hats and carbon steel brackets for durability and precise fitment
• High-quality KSport SC5 street brake pads included, with optional RC1 race pads available for more aggressive applications
• Two-piece floating disc assembly reduces unsprung and rotating weight for improved suspension response
• D.O.T. compliant components ensuring safety and street legality

Construction & Design:

The calipers are crafted from aircraft-quality billet aluminum, resulting in a lightweight yet extremely rigid structure that weighs just over 5 pounds each. Machined protection grooves on the bridge tubes add durability and resistance to wear. Aluminum pistons paired with high-temperature seals ensure reliable operation under extreme conditions, while stainless steel brake pad wear plates extend component life.

The 2-piece floating rotor design features a ventilated carbon steel disc mounted to a machined aluminum hat, optimizing heat dissipation and reducing overall weight. This construction minimizes unsprung mass, enhancing vehicle handling and braking responsiveness.

Installation & Fitment:

The KSport ProComp rear big brake kit is designed for straightforward installation on 2008–2015 Scion xB (xB2) models, requiring minimal tools in most cases. It fits vehicles equipped with 17-inch wheels or larger due to the rotor size. Note that the OEM handbrake function will not operate with this kit installed, so alternative parking brake solutions may be necessary.

What's Included:

• Pair of 4-piston billet aluminum rear calipers
• Two 13" (330mm) ventilated floating rotors
• Stainless steel braided brake lines
• Machined aluminum rotor hats
• Carbon steel mounting brackets
• KSport SC5 street brake pads
• All necessary hardware for installation

Ideal For:

This brake kit is ideal for Scion xB owners who demand improved braking performance for spirited street driving, occasional track days, or enhanced safety during daily use. It suits enthusiasts looking to upgrade from OEM brakes to a system that offers better heat management, reduced fade, and a more confident pedal feel without extensive modifications.