{"product_id":"heavy-duty-trailer-air-spring-w01-358-9978-s28929-1r12-668","title":"Heavy Duty Trailer Air Spring - W01-358-9978 S28929 1R12-668","description":"\u003cp\u003eRestore your commercial suspension's load-carrying capacity with this premium \u003cstrong\u003eHeavy Duty Trailer Air Spring\u003c\/strong\u003e by FleetPro Parts \u0026amp; Tires. Engineered as a direct aftermarket replacement rolling lobe\/reversible sleeve air spring, this unit provides superior load support, vibration dampening, and long service life. Whether you are hauling heavy freight across the Midwest or navigating rough construction sites, this air spring ensures your trailer remains level, protecting both your cargo and your chassis. We stock these heavily right here in our Hanover Park, Illinois warehouse to ensure lightning-fast shipping for fleets and owner-operators nationwide.\u003c\/p\u003e\n\n\u003ch2\u003eCommercial Load Support: The Heavy Duty Trailer Air Spring Advantage\u003c\/h2\u003e\n\n\u003cp\u003eThis \u003cstrong\u003eHeavy Duty Trailer Air Spring\u003c\/strong\u003e is overbuilt to survive the demanding environments of long-haul trucking. It features a premium 4.5–5.00 mm thick rubber construction that exceeds standard OEM requirements, heavily resisting dry rot, ozone cracking, and road debris. Furthermore, it is equipped with 4140-grade steel studs that are 25% stronger than standard hardware, preventing sheer failures under extreme articulation. Paired with a reinforced composite piston and an industry-leading leak test ratio, this aftermarket air spring delivers reliable, airtight performance shift after shift.\u003c\/p\u003e\n\n\u003cp\u003eAs we continue to grow the largest inventory of commercial truck parts in Illinois, we prioritize suspension hardware that balances industrial strength with cost-effective reliability. Serving as a direct exact-fit replacement for massive industry part numbers including Firestone W01-358-9978, Hendrickson S28929, and Goodyear 1R12-668, this unit is ready to bolt right on and save you from dealership markups. \u003cstrong\u003eImportant Fitment Note:\u003c\/strong\u003e Buying an air spring by make and model alone is not recommended. Always verify your replacement by crossing your original part number or measuring your top\/bottom plate mounting configurations prior to purchase.\u003c\/p\u003e\n\n\u003chr\u003e\n\n\u003ch3\u003eVehicle Fitment \u0026amp; Compatibility\u003c\/h3\u003e\n\u003cp\u003eThis premium aftermarket trailer air spring features a universal design intended for the following commercial applications:\u003c\/p\u003e\n\u003cul\u003e\n    \u003cli\u003e\n\u003cstrong\u003eMake:\u003c\/strong\u003e Universal Trailer Fit (Hendrickson, Freightliner, Volvo, Mack, Alliance, etc.)\u003c\/li\u003e\n    \u003cli\u003e\n\u003cstrong\u003eApplication:\u003c\/strong\u003e Trailer Air Suspension Systems\u003c\/li\u003e\n    \u003cli\u003e\n\u003cstrong\u003eSuspension Type:\u003c\/strong\u003e Rolling Lobe \/ Reversible Sleeve\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003chr\u003e\n\n\u003ch3\u003eDirect Replacement \u0026amp; Cross-Reference Numbers:\u003c\/h3\u003e\n\u003cp\u003e\u003cem\u003eThis air spring serves as a direct exact-fit replacement for the following part numbers:\u003c\/em\u003e\u003c\/p\u003e\n\u003cul\u003e\n    \u003cli\u003e\n\u003cstrong\u003eFirestone:\u003c\/strong\u003e W01-358-9978, W01-358-6262, W01-358-6231, 9978, 99978, 6262, 6231\u003c\/li\u003e\n    \u003cli\u003e\n\u003cstrong\u003eHendrickson:\u003c\/strong\u003e S28929, S-28929, C28929, HENS-28929\u003c\/li\u003e\n    \u003cli\u003e\n\u003cstrong\u003eGoodyear:\u003c\/strong\u003e 1R12-668, 1R12-1179, GYR1R12668, GYR-1R12-668, 8235FS9978\u003c\/li\u003e\n    \u003cli\u003e\n\u003cstrong\u003eContinental \/ ContiTech:\u003c\/strong\u003e 910-14P959, 910-17.5P831, 67588, 77303\u003c\/li\u003e\n    \u003cli\u003e\n\u003cstrong\u003eAutomann:\u003c\/strong\u003e 566.CT67588, AB1DK23I-A959, AB1DK23I-P959, AB1DK23P-6262\u003c\/li\u003e\n    \u003cli\u003e\n\u003cstrong\u003eMeritor:\u003c\/strong\u003e FS9978, FS6262, FS6231\u003c\/li\u003e\n    \u003cli\u003e\n\u003cstrong\u003eOther Aftermarket:\u003c\/strong\u003e TR9978 (Torque), AS-9978 (Triangle), 352-9978 \/ 452-9978L (Dayton), N32 559978 (Alliance), S28501 (Newstar)\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003chr\u003e\n\n\u003ch3\u003eTechnical Specifications\u003c\/h3\u003e\n\u003cul\u003e\n    \u003cli\u003e\n\u003cstrong\u003eTop Plate Diameter:\u003c\/strong\u003e 9.00\"\u003c\/li\u003e\n    \u003cli\u003e\n\u003cstrong\u003eTop Plate Hardware:\u003c\/strong\u003e 2 Bolt Holes (5.5\" Center-to-Center)\u003c\/li\u003e\n    \u003cli\u003e\n\u003cstrong\u003eBottom Plate Diameter:\u003c\/strong\u003e 10.24\"\u003c\/li\u003e\n    \u003cli\u003e\n\u003cstrong\u003eBottom Plate Hardware:\u003c\/strong\u003e 1 Bolt Hole (2.25\" Center-to-Center)\u003c\/li\u003e\n    \u003cli\u003e\n\u003cstrong\u003eExtended Length:\u003c\/strong\u003e Approx. 19.6\" - 22.00\"\u003c\/li\u003e\n    \u003cli\u003e\n\u003cstrong\u003eCompressed Length:\u003c\/strong\u003e Approx. 7.8\" - 8.20\"\u003c\/li\u003e\n    \u003cli\u003e\n\u003cstrong\u003ePiston Width:\u003c\/strong\u003e 8.05\"\u003c\/li\u003e\n    \u003cli\u003e\n\u003cstrong\u003eWarranty:\u003c\/strong\u003e 3-Year Unlimited Mile\u003c\/li\u003e\n    \u003cli\u003e\n\u003cstrong\u003eBrand:\u003c\/strong\u003e FleetPro Parts \u0026amp; Tires\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"FleetPro","offers":[{"title":"Default Title","offer_id":42619278229575,"sku":"FP-01-9978C","price":111.62,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0587\/8035\/2583\/files\/fp-01-9978c-heavy-duty-trailer-air-spring-w01-358-9978-s28929-1r12-668-fleetpro-2530464.jpg?v=1779136523","url":"https:\/\/fleetpropt.com\/products\/heavy-duty-trailer-air-spring-w01-358-9978-s28929-1r12-668","provider":"FLEETPRO PARTS \u0026 TIRES ","version":"1.0","type":"link"}