Wilwood 120-16683-BK 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 and demanding applications, this caliper combines lightweight construction with exceptional stopping power and durability.

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 internal stresses and grain structure interruptions that occur with traditional billet machining, resulting in superior strength and durability. Starting at just 4.9 pounds, the FNSL4R is engineered using computer-generated solid modeling and FEA stress analysis for optimized performance.

Key Features:

• Radial mounting design provides two planes of adjustment for precise disc alignment and simplified installation
• One-piece stainless steel pistons feature slow heat transfer properties and excellent corrosion resistance
• Available in multiple piston bore sizes for front or rear brake applications
• Compatible with Wilwood's Thermlock pistons (upgrade option) for enhanced thermal barrier protection
• SRS (Stainless Rotor Surface) bridge plates eliminate bridge wear from pad gouging and extend caliper service life
• Spring-loaded SRS plates eliminate pad rattle and dampen harmonic vibrations that cause pad squeal
• Two-piece bleed screws on each end with internal fluid crossovers protect against track debris damage
• High-temperature square-faced bore seals maximize sealing area and provide controlled piston retraction

Thermal Management:

The stainless steel pistons and optional Thermlock piston upgrades create an effective thermal barrier, reducing heat transfer from the brake pads to the 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.

Compatible with the full range of Wilwood pad compounds to match the brake response and heat requirements of competition racing, track days, and high-performance street driving applications.