Wilwood 120-11783 Forged Narrow Superlite Radial Mount Brake Caliper - 4R

The Wilwood Forged Narrow Superlite 4R (FNSL4R) radial mount disc brake caliper represents the latest evolution in high-performance braking technology. Designed for extreme environments across a wide range of motorsport and performance vehicle applications, this caliper combines big brake stopping power with precise fitment through radial mounting that provides two planes of adjustment for accurate rotor alignment.

Advanced Forged Construction:

Each caliper body is stress-flow forged from premium grade aluminum alloy billets, a process that re-aligns the metal's internal grain structure to flow within the contour of the caliper body. This eliminates the internal stresses and grain interruptions that occur when machining from straight billet, resulting in superior strength and durability. Starting at just 4.9 pounds, the FNSL4R design has been optimized using computer-generated solid modeling and FEA stress analysis technology.

Key Features:

• Stress-flow forged aluminum construction for maximum strength-to-weight ratio
• Radial mounting configuration simplifies installation and provides dual-plane adjustment
• One-piece stainless steel pistons with slow heat transfer properties and high corrosion resistance
• Available in multiple piston bore sizes for front or rear brake applications
• SRS (Slide Retaining Spring) bridge plates eliminate bridge wear from pad gouging and prevent pad rattle
• Two-piece bleed screws on each end with internal fluid crossovers for protected routing
• High-temperature square-faced bore seals provide maximum sealing area and controlled piston retraction
• Compatible with optional Thermlock pistons for enhanced thermal barrier performance
• Compatible with full range of Wilwood pad compounds

Performance Benefits:

The stainless steel pistons resist heat transfer and corrosion, while optional Thermlock pistons create an advanced thermal barrier that reduces heat migration from pads to caliper body, seals, and brake fluid. This thermal management results in cooler operating temperatures, extended component service life, and reduced risk of heat-induced brake fade. The SRS bridge plates not only extend caliper life by preventing wear, but also dampen harmonic vibrations that contribute to brake squeal.

Engineered for demanding competition and high-performance street applications where reliability, weight savings, and consistent braking performance are critical.