Wilwood Left Red TX4R Caliper, Radial Mount, 1.62/1.38-Inch Bores

This red Wilwood TX4R left brake caliper uses a 9.63-inch radial mount and the 1.25-inch rotor-width configuration. It is sold as one caliper, with its piston and mounting specification selected for the complete brake assembly. Based in Camarillo, California, Wilwood Engineering has its origins in the company Bill Wood founded in 1977. Its designs and manufactured disc brake products cover calipers and rotors alongside master cylinders, valves, fittings and lines. Motorsport, street-performance and specialized installations each require components selected for the complete system. The forged TX4R is a four-piston radial caliper intended for heavy vehicle brake assemblies. This exact 1.25-inch nominal-width unit differs from wider TX4R variants. Match the 10120 pad shape, bracket offset and available wheel space rather than relying on the family application summary.

Technical Details

• Manufacturer part number: 120-16731-RD
• Component: TX4R Forged Radial Mount; one individual caliper
• Placement: Left
• Construction and finish: Forged aluminum; Red Powder Coat
• Nominal rotor width: 1.25 inches
• Rotor width range: 1.17–1.25 inches
• Rotor diameter range: 14.25–16.00 inches
• Caliper weight reference: 13.4 lb
• Pistons: 4; stainless steel; bore dimensions 1.62/1.38 inches
• Hydraulic piston area: 3.56 square inches
• Dust boots: Yes
• Brake pad shape: 10120; shape number does not specify a friction compound
• Mounting interface: Radial; mounting centers 9.63 inches
• Mount height: 3.07 inches
• Hydraulic inlet thread: 1/8-27 NPT

Fitment & Compatibility

Compare the caliper drawing with your radial bracket before ordering. The 9.63-inch mounting centers and 1.62/1.38-inch bores must suit the installed rotor offset and hydraulic system. Use the left-hand caliper and keep the bleed arrangement in the specified orientation. A suitable pad sweep and clearance inside the wheel must be verified independently of rotor width.

Wilwood caliper specifications

For a modified brake system, provide its existing component specifications along with the vehicle details. PMB Performance has over 20 years of parts and fitment experience to help check the assembly before purchase.