Wilwood Right Aero4-ST Thermlock Caliper, Thick-Pad Configuration / 1.25-Inch Rotor Width

Four Thermlock pistons distinguish this right-hand AERO4/ST configuration. The insulated 1.88/1.62-inch differential bores are installed in a forged, Type III anodized body using type 6620 pads. Camarillo, California is home to Wilwood Engineering, the disc brake company Bill Wood founded in 1977. Its design and manufacturing range spans calipers, brake rotors, master cylinders, valves, fittings and brake lines for motorsport, street-performance and specialized brake systems.

Technical Details

• Manufacturer part number: 120-13297. Component: Aero4 Radial Mount caliper.
• Supply: one brake caliper, not a complete axle brake kit. Match the mating rotor, pads, bracket and connection hardware to the installation.
• Hydraulic inlet thread: 1/8-27 NPT. Use a fitting with the correct thread and sealing seat.
• Caliper weight: approximately 7.1 lb.
• Bore configuration 1.88/1.62 inches across 4 pistons; piston material: Thermlock. Hydraulic effective area: 4.84 square inches.
• Piston dust boots: not fitted.
• Pad fit is type 6620. Match the pad dimensions and compound to the rotor and intended braking conditions.
• Construction and surface: forged aluminum housing finished in Type III anodize.
• Nominal rotor width 1.25 inch; compatible outside diameter from 12.19 through 15.00 inches. Specified rotor-width limits: 1.10–1.28 inch.
• Bracket interface: 7.09-inch radial centers with 0.45-inch holes. Specified mount height: 2.09 inches; orientation: right hand.

Fitment & Compatibility

Confirm that the existing brake design calls for this Thermlock piston and pad arrangement. A matching 7.09-inch radial bracket must align a nominally 1.25-inch-wide rotor and clear the wheel at the completed installation offset.

Ask PMB Performance to check the complete brake arrangement before ordering. Our team brings over 20 years of experience; photographs and measured bracket and rotor dimensions make that check more useful.