Wilwood 120-16087 Aero4-ST Radial Mount 4-Piston Disc Brake Caliper Right-Hand

The Wilwood 120-16087 Aero4-ST is a forged four-piston radial mount disc brake caliper engineered for serious street performance and track use. As the latest evolution of the W4A/W6A caliper series, the Aero4-ST features redesigned internal fluid ports that eliminate the external fluid cross-over tubes and bulky center bridge assembly found on earlier designs — resulting in a cleaner, more rigid structure.

Key Features:

• Stress-flow forged aluminum body — premium-grade aluminum alloy billet is forged so the metal's internal grain structure flows within the contour of the caliper, delivering superior clamping efficiency and resistance to fatigue, stress, and distortion under load
• Four-piston design with 1.75", 1.50", and 1.25" piston bores for optimized pad pressure distribution
• Radial mount configuration — right-hand orientation for broad application compatibility
• Compatible rotor diameters from 12.88" to 15.00" to suit a wide range of heavy-duty braking setups
• 0.80" thick pad plate (6620 pad) — extended pad volume for improved heat endurance and longer pad life in high-demand racing conditions
• Thermlock piston technology — reduces heat transfer from rotor to brake fluid, protecting system integrity under sustained high-temperature use
• Type III hard anodized finish — provides a durable, corrosion-resistant surface

The Aero4-ST is sold individually and is designed for right-hand (R/H) installation. Its combination of race-derived engineering and broad rotor compatibility makes it a versatile choice for performance builds requiring reliable, high-clamping braking force.