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Product details
The polished left-rear GP310 is intended for the Harley-Davidson Dyna rear layout using Wilwood’s bottom-mounted bracket. Four stainless pistons provide hydraulic application in a billet aluminum housing. It has the 3.50-inch bracket pattern, with the installation-specific bracket supplied separately from the caliper. Founded in 1977 by Bill Wood, Wilwood Engineering is based in Camarillo, California. Its disc brake systems and components serve motorsport, street-performance and specialized applications. Calipers, brake rotors, master cylinders, valves, fittings and brake lines are among its products, selected according to the complete brake system’s requirements.
Technical Details
- Manufacturer part number: 120-7741-P
- Caliper type: GP310 Motorcycle Rear
- Construction: Billet Aluminium
- Finish: Polish
- Piston bores: 1.25 / 1.25 inches
- Piston type: Stainless
- Piston count: 4
- Published piston area: 2.46 square inches
- Dust boots: No
- Nominal rotor width: 0.25 inch
- Rotor thickness limits: 0.18–0.25 inches
- Rotor diameter limits: 9.00–11.50 inches
- Mounting style: Lug
- Mounting side: Left Hand
- Mounting centers: 3.50 inches
- Mounting-hole size: 0.39 inch
- Mount height: 1.55 inch
- Hydraulic inlet thread: 3/8-24
- Required pad shape: 6208
- Published pad area: 3.65 square inches
- Published pad volume: 0.63 cubic inches
- Manufacturer-listed component weight: 2.1 lb
- Supplied brake components: Individual GP310 caliper with brake pads
Fitment & Compatibility
Use FL186 to match the caliper with the Dyna bottom bracket and its documented application rather than assuming it uses the right-rear bracket. Confirm rotor thickness and centerline, the 3/8-24 inlet and pad sweep. Check clearance at the underside of the rotor and make sure the bleed point remains suitable for air removal.
PMB Performance has over 20 years of experience helping customers with brake and parts fitment. Share the installed component identification and relevant measurements when requesting assistance.
Brake-pad warning: Cancer and Reproductive Harm. www.P65Warnings.ca.gov. This warning applies to the brake pads.
