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Product details
A red XRS4R housing surrounds four equal 1.38-inch pistons on this Wilwood caliper. It is the narrower 0.81-inch nominal rotor-width configuration, with the forged body's X-shaped bridge linking the opposing piston banks. From its base in Camarillo, California, Wilwood Engineering designs and manufactures disc brake systems and components. Bill Wood founded the company in 1977; its motorsport, street-performance and specialized range includes calipers, brake rotors, master cylinders, valves, fittings and brake lines.
Technical Details
- Manufacturer part number: 120-17203-RD. Type: Forged XRS4R Radial Mount caliper.
- Caliper body: forged aluminum; finish: Red Powder Coat.
- Piston arrangement: 4 stainless steel pistons; bore specification 1.38/1.38 inches. Effective piston area: 3.00 square inches.
- Mounting: radial, 5.98-inch centers; orientation: universal. 0.39-inch holes; 1.45-inch mounting height.
- Component: one individual hydraulic brake caliper. Select the mating rotor, pads, mounting hardware and line connection to suit the complete brake assembly.
- Rotor channel: 0.81-inch nominal width. Specified width limits: 0.75–0.84 inch; rotor outside diameter: 11.75–14.00 inches.
- Brake pad shape: 10416. Choose pad dimensions and friction material for the brake system.
- Caliper component weight: approximately 4.9 lb.
- Hydraulic inlet thread: 1/8-27 NPT. Match the fitting thread and sealing arrangement to the brake hose.
- Piston dust boots: no.
Fitment & Compatibility
This caliper accepts an 11.75–14.00-inch rotor only when the bracket places the pad correctly. Verify the width, offset, hydraulic balance and wheel clearance together; diameter alone is not a fitment guarantee.
PMB Performance brings over 20 years of experience to brake-component selection. Share the installed caliper, rotor size and mounting arrangement so the relevant dimensions can be compared.
