King Engine Bearings CR4256XP0.5 Tri-Metal Connecting Rod Bearing Set +0.50mm Oversize

The King Engine Bearings CR4256XP0.5 is a high-performance connecting rod bearing set designed for the Dodge/Chrysler 148ci EDZ SRT-4 Turbocharged engine (2003–2009). This set features King's XP Racing series construction with the proprietary pMaxBlack™ tri-metal overlay, built specifically for demanding race and high-performance applications. This listing is for the +0.50mm oversize variant, intended for use with reground crankshaft journals.

pMaxBlack™ Tri-Metal Construction:

• Three-layer tri-metal design: Steel backing, copper-alloy intermediate layer, and a surface-hardened lead-tin-copper overlay electroplated onto a copper alloy substrate
• 5% copper overlay: Higher copper content than standard tri-metal bearings delivers a significant boost in fatigue strength and load capacity
• Nano-scaled hardening process: Proprietary surface treatment modifies the overlay's molecular structure, creating a black fatigue-resistant shield with 29% greater hardness (18.1 HV) over conventional overlays
• Superior load capacity: Rated up to 10,200 psi — a 24% increase over competitive race bearings
• Enhanced intermediate layer: Tin content increased to 4.5% (vs. 2–3% in standard bearings), raising intermediate layer hardness to 115 HV and load capacity to 17,000 psi
• SecureBond™ technology: Micro-etch surface preparation process that strengthens tri-metal structural integrity and reduces risk of layer delamination under extreme loads or metal-to-metal contact
• +0.50mm oversize: Designed for use after crankshaft journal regrinding to restore proper oil clearances

An optional upgrade to the King CR4256AM bimetal bearing, the CR4256XP series is engineered for race engines that operate under sustained high loads and high RPM conditions. King Engine Bearings manufactures all bearings in-house, with rigorous quality control checkpoints throughout production to ensure consistent wall thickness and dimensional accuracy. Cross-reference: Clevite CB-1668P, CB-1813A.