Wilwood 120-13263 FSL4R/ST Right Hand Disc Brake Caliper 1.25" Rotor

The Wilwood 120-13263 FSL4R/ST disc brake caliper delivers professional-grade braking performance with advanced differential bore piston technology and optional Thermlock® piston heat protection. Designed for sustained hard braking applications, this right-hand caliper features a durable Type III hard anodized finish that resists wear in demanding conditions across dirt ovals, asphalt tracks, off-road racing, rally, and road course competition.

Advanced Design Features:

• Redesigned internal fluid ports eliminate external crossover tubes for cleaner installation
• Dual bleed screw assemblies replace traditional transfer tubes
• Differential bore pistons (1.88" and 1.75") optimize pad wear characteristics
• Compatible with 1.25" thick rotors
• Right-hand orientation with no leading/trailing configuration required

Lightweight Forged Construction:

• Stress-flow forged from premium grade aluminum alloy billet
• Computer-modeled design maximizes strength while minimizing weight
• Assembled weight of just 4.4 pounds
• Closed-end bridges with radial transitions reduce stress concentrations
• Enhanced resistance to deflection under heavy braking loads

Engineered using advanced solid modeling and stress analysis technology, the FSL4R caliper eliminates machined steps and sharp shoulders in critical load-bearing areas, delivering measurable improvements in body strength and durability for professional racing applications.