Wilwood 120-16461 XRZ4R Radial Mount Brake Caliper, Left, 4 Piston

XRZ4R Radial Mount

Wilwood’s next-generation XRZero brake calipers combine decades of racing experience, computer Finite Element Analysis (FEA), and state-of-the-art machining to create a lighter, stiffer, zero-drag caliper. Its unique, high surface area body shape creates a caliper with superior brake fluid cooling and allows increased airflow through the rotor. Optimized profile high-temperature seals provide improved piston retraction, reducing drag. The unique X-bridge center reinforces the caliper body without adding mass or obstructing airflow to the rotor or pads.

Computer FEA design and precision CNC machining of the stress-flow forged aluminum body result in a caliper that weighs just 4.66 pounds (2.11 kg), a ½ pound (227 grams) lighter than a comparable size Wilwood Superlite caliper. The innovative and complex body shape removes unnecessary bulk, improves brake and fluid cooling, and reduces deflection. Four Thermlock® thermal barrier pistons reduce heat transfer to the brake fluid, and front calipers with stepped bores provide more even engagement with improved pad wear. Hard anodized internally in the piston bores and surface with a Type III ceramic aluminum oxide finish for durability, and equipped with single-point bleed technology and low-profile bleed screws for easy serviceability. Frictionless pad retention pins (spare included) hold your choice of Wilwood’s 0.80” thick competition compound brake pads for longer pad life. id="MainContent_lblPistType" class="Gray11B">Thermlock Dust Boot No

Rotor Dimensions

Rotor Width (in)	0.81
Rotor Diameter (in)	14.00

Pad Dimensions

Pad Area (in²)	8.2
Pad Volume (in³)	4.9

Service Rating & Material

Material	Forged Aluminum
Weight (lbs)	5.2

Colors & Finishes

Color
Finish	Type III Anodized

Mounting

Mount Center (in)	5.98
Mount Position
Mount Side	Left
Mount Type	Radial

Specifications

Rotor Compatibility

Rotor Width (in)	0.81
Max Rotor Width (in)	0.90
Min Rotor Width (in)	0.75
Max Rotor Diameter (in)	14.00
Min Rotor Diameter (in)	11.75

Brake Pad Specifications

Brake Pad Type 1	10420
Brake Pad Type 2	N-A
Brake Pad Type 3	N-A
Total Pad Area (in²)	8.2
Total Pad Volume (in³)	4.9
Mounting

Piston Specifications

Piston Bore 1 (in)	1.88
Piston Bore 2 (in)	1.75
Piston Bore 3 (in)
Total Piston Area (in²)	5.18

Mounting Specifications

Radial

Mount Side	Left
Mount Center (in)	5.98
Mount Hole Size (in)	0.39
Mount Height (in)	1.63
Inlet Thread Size	3/8-24