King Engine Bearings CR6640XP.026 XP-Series pMaxBlack Tri-Metal Connecting Rod Bearing Set

The King Engine Bearings CR6640XP.026 is an XP-Series performance connecting rod bearing set engineered for BMW M20 and M50 inline six-cylinder engines. This is a .026mm undersize set, designed for use with journals that have been machined undersized during an engine rebuild or performance build. King Engine Bearings has specialized exclusively in engine bearings since 1960, delivering precision components for automotive, motorsport, marine, and aviation applications.

At the heart of this bearing set is King's pMaxBlack™ tri-metal construction — a copper-lead bronze lining bonded to a steel backing, separated by a nickel barrier layer, and finished with a proprietary Babbitt overlay. The pMaxBlack™ overlay is nano-scaled hardened to modify its molecular structure, resulting in a fatigue-resistant black shield with a 29% increase in overlay hardness and an overall 24% increase in load capacity up to 10,200 PSI. This makes the XP-Series ideally suited for high-RPM, high-load performance and race engine applications.

Key Features:

• pMaxBlack™ Overlay — Proprietary nano-scaled hardening process for superior load capacity and fatigue resistance
• Tri-Metal Construction — Copper-lead bronze lining, nickel barrier, and hardened Babbitt overlay over a steel backing
• SecureBond™ Technology — Micro-etch surface preparation that maximizes tri-metal structural integrity and minimizes delamination risk under extreme loads
• Tightened Wall Thickness Tolerances — Maintained to ±0.0001 in. for precision fitment and consistent oil film support
• Narrowed Crank Cheek Profile — Increased crush height for improved bearing-to-bore contact, heat transfer, and reduced spin potential at high RPM
• Undersize: .026mm — For use with reground or machined crankshaft journals
• Designed for circle track, drag racing, offshore, and high-performance street applications utilizing forged steel crankshafts

The CR6640XP.026 is purpose-built for engine builders who demand reliable performance under sustained high loads. King's XP-Series bearings are a trusted choice in race shops worldwide where bearing precision and durability are non-negotiable.