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Product details
Wilwood XRZ4R-ST calipers must be matched by width and mounting configuration. This anodized brake caliper has 1.38/1.38-inch bore dimensions, a 5.98-inch mounting span and the 1.25-inch-wide rotor specification. 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. For motorsport, street-performance and specialized braking applications, Wilwood Engineering designs and manufactures disc brake systems and their individual components. Founded by Bill Wood in 1977 and based in Camarillo, California, Wilwood supplies a range encompassing calipers, rotors, master cylinders, valves, fittings and brake lines, all selected to match the complete system.
Technical Details
- Manufacturer part number: 120-16466
- Component: XRZ4R Radial Mount; one individual caliper
- Placement: Universal mounting orientation; verify axle position
- Construction and finish: Forged aluminum; Type III Anodize
- 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
- Pistons: 4; Thermlock insulated; bore dimensions 1.38/1.38 inches
- Hydraulic piston area: 3.00 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
Fitment & Compatibility
Choose this component around the existing rotor and bracket, including the 1.25-inch nominal rotor width and 5.98-inch mounting span. Axle placement is determined by the engineered brake package, not by a generic caliper designation. Compare pad support, caliper offset and piston volume with the brake being replaced. Wheel size alone cannot confirm spoke or barrel clearance.
Wilwood caliper specifications · Wilwood technical reference
Share the vehicle and the brake system actually installed with PMB Performance before ordering if the configuration is uncertain. We draw on over 20 years of parts and fitment experience when comparing the rotor, mount and caliper.
