SBM Main Bearing Set

The King Bearings SBM Main Bearing Set (MB 558SI) is engineered for builders and rebuilders who demand precision crankshaft support in high-performance engine applications. Main bearings are the foundation of any reliable powerplant—they support rotational loads, maintain critical oil film thickness, and directly influence engine longevity and reliability. Whether you're completing a full engine rebuild, upgrading from worn factory bearings, or building a modified engine platform, this bearing set delivers the precision fit and material consistency required for demanding automotive work.

King Bearings manufactures this main bearing set with advanced copper-lead overlay technology and controlled tolerances that ensure proper oil film formation under sustained load. The SBM designation indicates a standard bore main bearing design optimized for specific engine block geometries and crankshaft specifications. Precision manufacturing holds clearance tolerances within strict parameters, preventing bearing knock or catastrophic failure during startup, idle, cruise, and high-RPM operation. The compact package (7.09 × 3.54 × 1.57 inches, 1.24 lbs) fits standard main cap configurations while delivering the load-carrying capacity expected in competitive and street performance builds alike.

This bearing set is ideal for engine builders, performance shops, and experienced DIY mechanics performing complete engine assembly or reconditioning. Proper installation requires correct torque specification, clean oil galleries, and precise crankshaft and block alignment—standard procedures for any professional rebuild. Always verify fitment with your specific engine block and crankshaft before ordering, as main bearing sizes vary by manufacturer and displacement. Pair this bearing set with quality engine oil, proper break-in procedures, and regular maintenance intervals to ensure years of reliable service.