Wilwood Black GP310 Right Rear Motorcycle Sprocket Caliper, 1.25-Inch Pistons

Black powder coat finishes the right-hand GP310 sprocket-brake caliper. It is an individual four-piston component for a custom Harley-Davidson rear brake, with a 0.35-inch nominal rotor-width channel and a 3/8-24 threaded inlet. From its base in Camarillo, California, Wilwood Engineering designs and manufactures disc brake systems and components. Founded by Bill Wood in 1977, its range includes calipers, brake rotors, master cylinders, valves, fittings and brake lines for motorsport, street-performance and specialized applications.

Technical Details

• Manufacturer part number: 120-10174-BK. Component: GP310 Motorcycle Rear (Sprocket Brake) caliper.
• Supply: one brake caliper, not a complete axle brake kit. Match the mating rotor, pads, bracket and connection hardware to the installation.
• Piston dust boots: not fitted.
• Caliper weight: approximately 2.3 lb.
• Hydraulic inlet thread: 3/8-24. Use a fitting with the correct thread and sealing seat.
• Compatible brake pad shape: 6208; choose the required compound for the brake system.
• Rotor compatibility: nominal width 0.35 inch; diameter 9.00–11.50 inches. Specified rotor-width limits: 0.29–0.35 inch.
• Pistons: 4 stainless steel; bore specification: 1.25 inches. Effective piston area: 2.46 sq in.
• Mounting: lug, 3.50-inch centers; right hand orientation. Mount holes: 0.39 inch.
• Body: billet aluminum; finish: Black powder coat.

Fitment & Compatibility

Check the custom bracket's 3.50-inch lug pattern and the sprocket's braking surface. This rear sprocket version should not be substituted for a front fork-mount GP310 simply because both share the same family name.

With 20+ years of experience, PMB Performance can help compare the actual brake hardware. Supply the caliper number, rotor dimensions and mounting measurements when asking about compatibility.