Clevite MS-2056A-.25MM Performance Main Bearing Set Undersize

The Clevite MS-2056A-.25MM is a high-performance engine crankshaft main bearing set designed for demanding applications. This undersize bearing set (-.25MM) is engineered to provide optimal oil film thickness and bearing life in performance and racing engines.

Advanced Bearing Design:

Clevite's engineering demonstrates that a 180-degree groove in the upper main shell provides the best overall bearing performance. This design maintains optimal oil film development while efficiently feeding connecting rod bearings. The lower shells feature no grooving, allowing the crankshaft to develop a thicker oil film for improved load capacity and extended bearing life. Extended grooves into the lower bearing half actually reduce performance without providing benefits, while also increasing horsepower loss and peak oil film pressure.

Performance Series Options:

• P-Series: Maximum eccentricity with full groove designs, hardened steel backing, high crush retention, and reduced overlay thickness to prevent fatigue. Ideal for extreme RPM applications with severe rod bore deformation
• H-Series: Medium eccentricity with enlarged chamfers for oversized crankshaft fillets, thin overlay, and no flash plating for superior seating. Developed for NASCAR and suitable for all competition engines running medium to high RPM
• K-Series (TriArmor): Features proprietary moly/graphite surface treatment with PTFE carrier for exceptional start-up protection and high-load performance across broad temperature ranges
• V-Series: Lead-indium overlay construction offering superior conformability with slightly reduced wear resistance compared to lead-tin-copper overlays
• M-Series (Micro): Special .006-inch thick babbitt lining on hardened steel providing extreme conformability for engines with severe crankshaft deflection and edge loading conditions

Key Features:

• Undersize bearing set (-.25MM) for reground crankshafts
• TriMetal construction for strength and durability
• Optimized groove patterns for maximum oil film development
• High crush design for secure retention
• Hardened steel backing on select series for added strength
• Enlarged chamfers available for increased fillet clearance
• Multiple series available for specific performance requirements

Clevite bearings are engineered using extensive testing and analysis to deliver superior performance in racing and high-performance street applications. The bearing design focuses on maintaining proper oil film separation between the bearing surface and crankshaft, similar to hydroplaning, while minimizing grooving that would disrupt this critical oil film.