Clevite MS-1533P-.25MM High Performance Main Bearing Set .25mm Undersize

The Clevite MS-1533P-.25MM is a high-performance main bearing set designed for engines requiring .25mm undersize bearings. This precision-engineered bearing set provides the critical oil film separation between crankshaft and engine block needed for reliable performance in demanding applications.

Advanced Bearing Design:

This bearing set features optimized groove design for superior performance. The upper main shells incorporate a 180-degree oil groove that effectively supplies oil to connecting rod bearings while maintaining maximum oil film thickness in loaded areas. The lower shells are ungrooved, allowing development of a thicker protective oil film that provides greater safety margins and extended bearing life compared to older full-grooved designs.

P-Series Performance Features:

• High eccentricity design for optimized load distribution and contact patterns
• Increased crush for maximum bearing retention in the bore
• Reduced overlay thickness to prevent overlay fatigue and hen tracking
• Full groove configuration for maximum oil flow to rod bearings
• Hardened steel back construction for added strength and fretting resistance
• TriMetal construction combining durability with excellent bearing properties

Ideal Applications:

P-Series bearings excel in high-RPM racing engines where rod bearing oil starvation may be an issue. Use this series when you need higher eccentricity to narrow bearing contact patterns and provide increased oil delivery to connecting rod bearings. These bearings are particularly effective when rod bearing damage shows polishing, smearing, or discoloration concentrated at the bearing's axial center—classic indicators of oil starvation.

The .25mm undersize specification makes this set ideal for crankshafts that have been machined undersize during reconditioning or performance building. Clevite's TriMetal bearing technology provides the strength and durability required for competition and high-performance street applications.