{"product_id":"action-clutch-04-21-subaru-wrx-sti-2-5l-dohc-ej257-oe-hd-flywheel","title":"Action Clutch OE-HD Flywheel – 2004-2021 Subaru WRX STI 2.5L DOHC EJ257 | Heavy-Duty Direct Replacement (AONAC117FW-OEHD)","description":"\u003ch3\u003eAction Clutch OE-HD Flywheel – 2004–2021 Subaru WRX STI 2.5L DOHC EJ257 | Heavy-Duty Direct Replacement\u003c\/h3\u003e\u003cp\u003eThe Action Clutch OE-HD Flywheel for the 2004–2021 Subaru WRX STI with the 2.5L DOHC EJ257 engine is a heavy-duty direct replacement flywheel engineered to exceed OEM specifications — delivering improved material strength and durability over the factory flywheel while maintaining the OE weight and rotational mass characteristics for smooth, streetable clutch engagement. The OE-HD designation indicates a flywheel that matches the factory flywheel's dimensions and weight profile (OE) while being built to a higher-duty specification (HD) — correct for EJ257 STI owners who want a stronger, more durable flywheel replacement without the drivability trade-offs of a lightweight flywheel. For STI owners replacing their clutch who want a new flywheel rather than a resurfaced OEM unit, the Action Clutch OE-HD flywheel is the correct, performance-grade replacement.\u003c\/p\u003e\u003ch4\u003eKey Features:\u003c\/h4\u003e\u003cul\u003e\n\u003cli\u003eOE-HD specification — OE weight and dimensions with heavy-duty material and construction — stronger than the factory flywheel while maintaining factory rotational mass characteristics for smooth, streetable drivability\u003c\/li\u003e\n\u003cli\u003eDirect bolt-in replacement — engineered as a direct replacement for the factory flywheel on the 2004–2021 Subaru WRX STI EJ257 — no modification required\u003c\/li\u003e\n\u003cli\u003eHeavy-duty construction — built to exceed OEM material specifications for improved resistance to heat cracking, surface wear, and structural fatigue under the elevated loads of performance and track use\u003c\/li\u003e\n\u003cli\u003eEJ257 specific — engineered for the 2.5L DOHC EJ257 engine as fitted to the 2004–2021 WRX STI — correct flywheel dimensions, bolt pattern, and ring gear specification\u003c\/li\u003e\n\u003cli\u003eMaintains OE drivability — OE-weight flywheel maintains factory rotational mass for smooth clutch engagement and normal idle — no drivability trade-offs vs. lightweight alternatives\u003c\/li\u003e\n\u003cli\u003eAction Clutch quality — manufactured by Action Clutch, a respected US performance clutch and drivetrain component brand\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch4\u003eOE-HD vs. Lightweight Flywheel — Which Is Right for Your STI?\u003c\/h4\u003e\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eOE-HD Flywheel (this product):\u003c\/strong\u003e OE weight with heavy-duty construction. Correct for street performance and occasional track use where drivability is important alongside durability. Smooth clutch engagement and normal idle maintained.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eLightweight Flywheel:\u003c\/strong\u003e Reduced rotational mass for faster revving and improved throttle response. Correct for dedicated track and competition builds. Trade-offs include rougher idle, more sensitive clutch engagement, and reduced low-speed drivability.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eSummary:\u003c\/strong\u003e Street-driven or occasional track STI — choose OE-HD. Dedicated track or competition car — consider lightweight.\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch4\u003eWhy Replace Instead of Resurface?\u003c\/h4\u003e\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eCost and Convenience:\u003c\/strong\u003e A new flywheel eliminates the machine shop step — install directly from the box with a guaranteed fresh friction surface.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eResurfacing Limits:\u003c\/strong\u003e Flywheels can only be resurfaced a limited number of times — a previously resurfaced flywheel may not have sufficient material remaining for another safe resurface.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eHeat Cracking:\u003c\/strong\u003e Track use can cause heat cracking in the friction surface. A cracked flywheel cannot be resurfaced. The OE-HD's heavy-duty construction provides improved heat crack resistance over the factory unit.\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch4\u003eSpecifications:\u003c\/h4\u003e\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eBrand:\u003c\/strong\u003e Action Clutch\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003ePart Number:\u003c\/strong\u003e AONAC117FW-OEHD\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eSpecification:\u003c\/strong\u003e OE-HD (OE weight, heavy-duty construction)\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eApplication:\u003c\/strong\u003e 2004–2021 Subaru WRX STI — 2.5L DOHC EJ257\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eWeight:\u003c\/strong\u003e 26 lbs (shipping weight)\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch4\u003eFitment Information:\u003c\/h4\u003e\u003cul\u003e\n\u003cli\u003e\u003cstrong\u003e2004–2021 Subaru WRX STI — 2.5L DOHC EJ257 — manual transmission only\u003c\/strong\u003e\u003c\/li\u003e\n\u003cli\u003eThe EJ257 was used across GD, GR\/GV, and VA STI chassis — verify that AONAC117FW-OEHD is the correct flywheel for your specific chassis and model year before ordering.\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch4\u003eWhat’s Included:\u003c\/h4\u003e\u003cul\u003e\n\u003cli\u003eAction Clutch OE-HD flywheel — 2004–2021 Subaru WRX STI EJ257 (AONAC117FW-OEHD)\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eFlywheel bolts not included\u003c\/strong\u003e — EJ257 flywheel bolts are stretch bolts and must be replaced with new OEM bolts. Do not reuse old flywheel bolts.\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch4\u003eInstallation Notes:\u003c\/h4\u003e\u003cul\u003e\n\u003cli\u003eProfessional installation by an experienced Subaru drivetrain specialist strongly recommended\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eDo not reuse old flywheel bolts\u003c\/strong\u003e — EJ257 flywheel bolts are stretch bolts — source new OEM Subaru flywheel bolts before installation\u003c\/li\u003e\n\u003cli\u003eClean crankshaft flange and flywheel mating surface thoroughly before installation\u003c\/li\u003e\n\u003cli\u003eVerify flywheel runout after installation using a dial indicator\u003c\/li\u003e\n\u003cli\u003eInstall a new clutch disc and pressure plate alongside the new flywheel\u003c\/li\u003e\n\u003cli\u003eUse a clutch alignment tool to correctly centre the clutch disc before torquing the pressure plate\u003c\/li\u003e\n\u003cli\u003eBed in the new clutch correctly — avoid aggressive clutch engagement for the first 500–1,000 km\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch4\u003eWhy Action Clutch?\u003c\/h4\u003e\u003cp\u003eAction Clutch is a US performance clutch and drivetrain component brand with a strong following in the Subaru and Japanese performance community — known for their clutch kits, flywheels, and drivetrain components for a wide range of performance platforms. The OE-HD flywheel lineup delivers improved material strength and a guaranteed fresh friction surface at a price point that makes replacement the correct choice over resurfacing.\u003c\/p\u003e\u003ch4\u003ePerfect For:\u003c\/h4\u003e\u003cul\u003e\n\u003cli\u003e2004–2021 Subaru WRX STI EJ257 owners replacing their clutch who want a new, heavy-duty flywheel rather than a resurfaced OEM unit\u003c\/li\u003e\n\u003cli\u003eSTI owners whose factory flywheel is heat-cracked, excessively worn, or has been previously resurfaced\u003c\/li\u003e\n\u003cli\u003eStreet performance and occasional track STI builds where OE-weight drivability is important alongside improved flywheel durability\u003c\/li\u003e\n\u003cli\u003eOwners completing a full clutch system replacement for a complete EJ257 drivetrain refresh\u003c\/li\u003e\n\u003c\/ul\u003e\u003cp\u003e\u003cstrong\u003eNote:\u003c\/strong\u003e Manual transmission only. EJ257 flywheel bolts are stretch bolts — do not reuse, source new OEM bolts. Install alongside new clutch disc and pressure plate. Verify model year and chassis fitment before ordering. Bed in correctly after installation.\u003c\/p\u003e","brand":"Action Clutch","offers":[{"title":"Default Title","offer_id":47999507955879,"sku":"AONAC117FW-OEHD","price":182.23,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0555\/8344\/1063\/files\/ActionClutchCanadaAC117FW-OEHD_a17945c0-210f-45a5-8fbd-8277d75649f8.png?v=1779914357","url":"https:\/\/www.straightsiximports.com\/en-us\/products\/action-clutch-04-21-subaru-wrx-sti-2-5l-dohc-ej257-oe-hd-flywheel","provider":"Straight Six Imports","version":"1.0","type":"link"}