Wilwood Right FSL4R Radial Brake Caliper, 1.88/1.75-Inch Stainless Bores / 1.25-inch Rotor Width: Gray radial-mount Superlite with white lettering and piston-count marking, central bridge bolt and open pad channel.

Wilwood Right FSL4R Radial Brake Caliper, 1.88/1.75-Inch Stainless Bores / 1.25-inch Rotor Width

SKU: 120-13227

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Product details

Wilwood’s right Forged Superlite 4R uses two pairs of stainless pistons in 1.88- and 1.75-inch bores. This is the radial-mount version for a nominal 1.25-inch rotor width, with internal fluid transfer and a Type III anodized surface. This component comes from Wilwood Engineering, established in 1977 by Bill Wood and based in Camarillo, California. Its disc brake design and manufacturing work includes calipers, brake rotors, master cylinders, valves, fittings and brake lines for motorsport, street-performance and specialized systems.

Technical Details

  • Manufacturer part number: 120-13227. Component: Forged Superlite 4 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.
  • Piston dust boots: not fitted.
  • Nominal rotor width 1.25 inch; compatible outside diameter from 11.75 through 14.00 inches. Specified rotor-width limits: 1.15–1.35 inch.
  • Construction and surface: forged aluminum housing finished in Type III anodize.
  • Hydraulic inlet thread: 1/8-27 NPT. Use a fitting with the correct thread and sealing seat.
  • Bracket interface: 5.98-inch radial centers with 0.39-inch holes. Specified mount height: 1.63 inches; orientation: right hand.
  • Pad fit is type 7420. Match the pad dimensions and compound to the rotor and intended braking conditions.
  • Caliper weight: approximately 5.2 lb.
  • Bore configuration 1.88/1.75 inches across 4 pistons; piston material: stainless steel. Hydraulic effective area: 5.18 square inches.

Fitment & Compatibility

Compare the 5.98-inch stud pattern and the caliper’s radial position against the bracket drawing. A rotor between 11.75 and 14.00 inches in diameter must also fall within the 1.15–1.35-inch width range, with the correct pad contact area.

For a replacement or custom installation, send PMB Performance the brake dimensions and existing component identification. Our 20+ years of experience can help narrow down the correct combination.