Wilwood 120-13264 FSL4R Left Hand Disc Brake Caliper 1.25" Rotor 1.88"/1.75" Pistons

The Wilwood 120-13264 FSL4R/ST disc brake caliper delivers professional-grade braking performance with differential bore piston technology and optional Thermlock® heat protection. Engineered for sustained hard braking on dirt and asphalt ovals, off-road, rally, and road course applications, this left-hand caliper is designed for 1.25-inch rotors with 1.88-inch and 1.75-inch differential bore pistons.

Key Features:

• Redesigned internal fluid ports eliminate external crossover tubes for cleaner installation
• Dual bleed screw assemblies allow left/right hand orientation without leading/trailing configuration
• Stress-flow forged from premium grade aluminum alloy billet for maximum strength
• Type III hard anodized finish provides superior wear resistance and corrosion protection
• Computer-modeled closed-end bridge design with radial transitions reduces stress concentrations
• Lightweight construction at approximately 4.4 pounds assembled weight
• Enhanced body strength with improved resistance to deflection under load

The FSL4R caliper body represents advanced engineering through solid modeling and finite element stress analysis, eliminating machined steps and sharp shoulders in critical load-bearing areas. This results in measurable improvements in structural integrity and consistent performance under extreme braking conditions.