Fitment questions?
Call (855) 786-7101 or text (801) 304-3141. We check fitment by VIN.
Product details
The polished right-rear GP310 is an individual four-piston caliper for compatible Harley-Davidson rear-brake packages. Its billet aluminum body attaches through a 3.50-inch lug pattern to the required rear bracket. The separate bracket determines the model-specific installation and is not part of this caliper listing. 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: 120-7740-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: Right 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
Match the caliper and rear bracket as a pair before confirming motorcycle fitment. Check rotor diameter, thickness and offset against the assembly drawing and inspect the pad track. The right-hand body, 3/8-24 inlet and wheel clearance must also agree with the installed layout, particularly on bikes with modified hubs or final-drive components.
With over 20 years of parts experience, PMB Performance can help compare this component with your existing brake assembly. Include its caliper reference and any conversion-kit information.
Brake-pad warning: Cancer and Reproductive Harm. www.P65Warnings.ca.gov. This warning applies to the brake pads.
