{"product_id":"wilwood-caliper-gp310-black-front-l-h-08-curnt-1-25in-pistons-25in-disc","title":"Wilwood GP310 4-Piston Brake Caliper | Front Left-Hand | Harley-Davidson 2008–Present | Black | 120-12117-BK","description":"\u003ch2\u003eWilwood GP310 4-Piston Brake Caliper – Front Left-Hand | Harley-Davidson 2008–Present | Black | 120-12117-BK\u003c\/h2\u003e\n\n\u003cdiv style=\"border-left: 4px solid #333; padding: 10px 16px; margin-bottom: 16px; background: #f9f9f9;\"\u003e\n\u003cp\u003e\u003cstrong\u003e⚠️ Safety-critical brake component — motorcycle application.\u003c\/strong\u003e This is a front left-hand caliper for 2008–present Harley-Davidson motorcycles. For dual disc setups, both a left-hand and right-hand caliper are required — this listing covers the left side only. Professional installation and full brake system bleed required. Confirm rotor thickness is .25\" minimum before installation. Pads not included — source GP310-compatible Wilwood pads separately.\u003c\/p\u003e\n\u003c\/div\u003e\n\n\u003cp\u003eWilwood 120-12117-BK GP310 4-piston billet aluminium brake caliper for 2008–present Harley-Davidson motorcycles. Front left-hand position, black anodised finish, direct fork leg mount — no brackets required. A significant performance and aesthetic upgrade over the OEM sliding single-piston caliper. 2.1 lbs. Ships fast across Canada and the US.\u003c\/p\u003e\n\n\u003ch3\u003eGP310 — Purpose-Built for Harley-Davidson\u003c\/h3\u003e\n\u003cp\u003eWilwood’s GP310 is a motorcycle-specific caliper engineered for direct installation on 2008-and-newer Harley-Davidson Big Twin and Sportster models equipped with the leg-mount caliper bracket system. The GP310 uses Harley’s OEM caliper mounting boss locations on the fork leg — bolt-on installation without fabrication, custom brackets, or modification to the fork leg. Available for single disc models (one caliper) and dual disc models (L\/H and R\/H pair required).\u003c\/p\u003e\n\n\u003ch3\u003e4-Piston Fixed Caliper — Performance Upgrade\u003c\/h3\u003e\n\u003cp\u003eThe OEM Harley-Davidson front brake caliper is a single-piston sliding design — functional for stock riding conditions but limited in braking force, modulation, and heat management for performance or heavily loaded riding. The Wilwood GP310 replaces this with a 4-piston fixed monoblock caliper:\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003e4 pistons (2 per side):\u003c\/strong\u003e Even clamping force applied symmetrically across the brake pad face. Eliminates the uneven pad wear and flex inherent in sliding caliper designs. More consistent braking feel throughout the pad’s service life.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eFixed monoblock design:\u003c\/strong\u003e The caliper body is one solid piece of billet aluminium — no flex between caliper halves under hard braking loads. Direct, immediate brake response.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eGreater braking force:\u003c\/strong\u003e Four pistons operating at the same hydraulic pressure as a single-piston OEM caliper generate significantly more total clamping force — shorter stopping distances and more consistent brake feel at higher speeds and loads.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eBillet Aluminium Construction — Black Anodised\u003c\/h3\u003e\n\u003cp\u003eCNC-machined from solid 6061 billet aluminium — lighter than OEM iron or cast caliper designs and with superior heat dissipation characteristics. The black anodised finish is durable, corrosion-resistant, and provides a clean blacked-out aesthetic that suits most custom Harley builds. At 2.1 lbs, the GP310 is significantly lighter than a comparable iron caliper.\u003c\/p\u003e\n\n\u003ch3\u003ePiston and Rotor Specification\u003c\/h3\u003e\n\u003cp\u003eThe GP310 120-12117-BK uses 1.25-inch diameter pistons and is designed for use with brake rotors of .25-inch (6.35mm) minimum thickness. Verify your front rotor meets the minimum thickness specification before installation — a rotor below minimum thickness combined with an upgraded caliper’s increased clamping force accelerates rotor wear and can cause rotor failure. Wilwood GP310-specific brake pads are required — source separately to complete the brake system upgrade.\u003c\/p\u003e\n\n\u003ch3\u003eFront Left-Hand — Dual Disc Buyers\u003c\/h3\u003e\n\u003cp\u003eThis listing is the front \u003cstrong\u003eleft-hand\u003c\/strong\u003e caliper only (from the rider’s seated perspective). For single disc Harley models, one caliper covers the entire front brake. For dual disc models (where two rotors and two calipers are fitted to the front wheel), both a left-hand (120-12117-BK) and a right-hand caliper are required. Confirm your model’s front brake configuration before ordering.\u003c\/p\u003e\n\n\u003cp\u003e\u003cem\u003eMotorcycle brake component — safety-critical. Professional installation required. Full brake system bleed mandatory after installation. Pads and rotor not included. Left-hand caliper only — dual disc requires both sides.\u003c\/em\u003e\u003c\/p\u003e\n\n\u003ch3\u003eSpecifications\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003eBrand: Wilwood\u003c\/li\u003e\n\u003cli\u003ePart Number: 120-12117-BK\u003c\/li\u003e\n\u003cli\u003eModel: GP310\u003c\/li\u003e\n\u003cli\u003eType: 4-piston fixed monoblock brake caliper\u003c\/li\u003e\n\u003cli\u003ePosition: Front left-hand\u003c\/li\u003e\n\u003cli\u003ePiston diameter: 1.25\"\u003c\/li\u003e\n\u003cli\u003eMinimum rotor thickness: .25\"\u003c\/li\u003e\n\u003cli\u003eFinish: Black anodised\u003c\/li\u003e\n\u003cli\u003eConstruction: Billet 6061 aluminium\u003c\/li\u003e\n\u003cli\u003eMount: Direct fork leg mount\u003c\/li\u003e\n\u003cli\u003eApplication: 2008–present Harley-Davidson (single and dual disc models)\u003c\/li\u003e\n\u003cli\u003eWeight: 2.1 lbs\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"Wilwood","offers":[{"title":"Default Title","offer_id":51349629763751,"sku":"WIL120-12117-BK","price":277.62,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0555\/8344\/1063\/files\/4c256fcdca9e599b44f09399cf7df2eb.jpg?v=1789666940","url":"https:\/\/www.straightsiximports.com\/en-us\/products\/wilwood-caliper-gp310-black-front-l-h-08-curnt-1-25in-pistons-25in-disc","provider":"Straight Six Imports","version":"1.0","type":"link"}