Wilwood Red XRS4R Four-Piston Caliper, Large-Bore 4.80-Square-Inch Configuration

The red Wilwood XRS4R shown here is the four-piston 1.75-inch-bore configuration. A 4.80-square-inch effective area is combined with a nominal 1.10-inch rotor width; this identifies a specific caliper rather than a universal replacement for any four-piston brake. Wilwood Engineering was founded by Bill Wood in 1977 and is based in Camarillo, California. The company designs and manufactures disc brake systems and components, including calipers, brake rotors, master cylinders, valves, fittings and brake lines for motorsport, street-performance and specialized applications.

Technical Details

• Manufacturer part number: 120-17206-RD. Type: Forged XRS4R Radial Mount caliper.
• 4-piston hydraulic layout with 1.75/1.75-inch bores and 4.80 sq in of effective area; piston type: stainless steel.
• Nominal rotor width 1.10 inch; compatible width range 1.00–1.10 inch. Rotor diameter specification: 11.75–14.00 inches.
• 5.98-inch-center radial attachment, universal orientation. 0.39-inch holes; 1.45-inch mounting height.
• Hydraulic inlet thread: 1/8-27 NPT. Match the fitting thread and sealing arrangement to the brake hose.
• Red Powder Coat finish on a forged aluminum body.
• Compatible pad profile 10416; confirm thickness and compound for the installation.
• Component: one individual hydraulic brake caliper. Select the mating rotor, pads, mounting hardware and line connection to suit the complete brake assembly.
• Piston dust boots: no.
• Caliper component weight: approximately 5.0 lb.

Fitment & Compatibility

Check the rotor's diameter and the bracket's mounting height together to establish pad sweep. The correct 10416 pads, fitting seat and hose route also form part of the compatibility assessment.

PMB Performance has over 20 years of brake-component experience. Send the existing caliper identification, rotor measurements and mounting details for help comparing this configuration.