KSport ProComp Rear Big Brake Kit

2008–2015 Scion xB (xB2)

BKSC040-852SO

Overview:

The KSport ProComp 15" 8-Piston Rear Big Brake Kit is engineered to deliver exceptional stopping power for the 2008 to 2015 Scion xB (xB2). Designed for enthusiasts seeking enhanced braking performance and reliability, this kit integrates advanced brake technology to reduce fade and maintain consistent pad contact during aggressive driving. Whether on the street or track, the ProComp kit offers a significant upgrade over the factory braking system, improving safety and control under demanding conditions.

Ideal for drivers who demand precision and confidence in their braking, this rear big brake kit transforms the Scion xB’s rear braking capability with high-quality components and a performance-focused design.

Key Features:

The KSport ProComp Rear Big Brake Kit combines innovative engineering and premium materials to ensure superior braking performance. Key features include:

• 8-piston aluminum calipers for increased clamping force and improved pad wear
• D.O.T. compliant stainless steel brake lines that resist expansion under pressure for consistent pedal feel
• 380mm (15") large ventilated discs designed to dissipate heat efficiently and reduce brake fade
• Machined aluminum hats and carbon steel brackets for lightweight strength and durability
• High-quality KSport SC5 street brake pads included, with optional RC1 race pads available
• Opposed piston caliper design enhances rigidity and pad contact compared to OEM brakes
• Two-piece floating disc assembly reduces rotating and unsprung weight for better handling
• Aircraft-quality billet aluminum calipers weighing just over 5 lbs. each
• Aluminum pistons and high-temperature seals for reliable operation under extreme conditions
• Machined protection grooves on calipers to safeguard bridge tubes

Construction & Design:

The ProComp brake kit features calipers machined from aircraft-grade billet aluminum, ensuring a lightweight yet robust structure that withstands high stress and heat. The 8-piston configuration is arranged in a differential bore layout to optimize pad wear and braking efficiency. High-temperature seals and aluminum pistons contribute to durability and consistent performance, while stainless steel brake pad wear plates protect critical surfaces.

The floating two-piece disc design combines a vented carbon steel rotor with a machined aluminum hat, reducing unsprung mass and improving heat dissipation. This construction enhances both braking response and vehicle handling, making it suitable for spirited driving and track use.

Installation & Fitment:

Installation of the KSport ProComp Rear Big Brake Kit is designed to be straightforward, requiring minimal tools in most cases. The kit is a direct fit for 2008–2015 Scion xB (xB2) models, though it requires 19" wheels to accommodate the larger 380mm rotors. Note that the OEM handbrake function will not operate with this kit installed, so alternative parking brake solutions may be necessary.

What's Included:

• 8-piston billet aluminum rear calipers
• 380mm ventilated two-piece floating rotors
• Stainless steel braided brake lines
• Machined aluminum hats and carbon steel mounting brackets
• KSport SC5 street brake pads
• All necessary hardware for installation

Ideal For:

This big brake kit is perfect for Scion xB owners looking to upgrade their rear braking system for improved performance, whether for spirited street driving, autocross, or track days. It suits enthusiasts who prioritize brake feel, fade resistance, and overall stopping power without compromising vehicle handling.