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Product details
The anodized right Wilwood XRZ4R-ST is an individual brake caliper. It combines a 5.98-inch attachment span with 1.88/1.75-inch piston bores; confirm the rotor centerline and 1.25-inch width configuration before installation. XRZ4R-ST is a forged four-piston radial race caliper with Thermlock pistons and an X-shaped center bridge. It uses 10420-shape pads and a 3/8-24 hydraulic inlet. Confirm the brake bracket and piston volume when replacing another radial caliper. Bill Wood established Wilwood Engineering in 1977. From Camarillo, California, the company designs and manufactures calipers, rotors, master cylinders, valves, fittings and brake lines as part of its disc brake range. Its motorsport, street-performance and specialized products are chosen around the requirements of the whole braking system.
Technical Details
- Manufacturer part number: 120-16460
- Component: XRZ4R Radial Mount; one individual caliper
- Placement: Right
- Construction and finish: Forged aluminum; Type III Anodize
- Pistons: 4; Thermlock insulated; bore dimensions 1.88/1.75 inches
- Hydraulic piston area: 5.18 square inches
- Dust boots: No
- Brake pad shape: 10420; shape number does not specify a friction compound
- Mounting interface: Radial; mounting centers 5.98 inches
- Mounting-hole diameter: 0.39 inches
- Mount height: 1.63 inches
- Hydraulic inlet thread: 3/8-24
- Nominal rotor width: 1.25 inches
- Rotor width range: 1.15–1.35 inches
- Rotor diameter range: 11.75–14.00 inches
- Caliper weight reference: 5.4 lb
Fitment & Compatibility
Check bracket location and rotor sweep using the installation drawing; 5.98-inch radial mounting alone does not establish a vehicle fit. Use the right-hand caliper and keep the bleed arrangement in the specified orientation. Use the 1.88/1.75-inch piston-bore specification when reviewing hydraulic balance, and verify hose routing and wheel clearance.
Wilwood caliper specifications · Wilwood technical reference
PMB Performance brings over 20 years of parts and fitment experience to brake component selection. A photograph of the existing brake and its mounting measurements helps us check the required configuration.
