ACL Bearings 5M1883-.25 Race Series Main Bearing Set Undersize - 25mm

The ACL Bearings 5M1883-.25 is a high-performance crankshaft main bearing set designed for engine rebuilds requiring .25mm (.010") undersize bearings. This Race Series bearing set delivers the proven durability and precision that ACL has been known for in motorsports since the 1960s.

Race-Proven Engineering:

• Tri-metal construction combining high strength with excellent seizure resistance for demanding applications
• Hardened steel backing improves support and bearing retention in the housing
• 3/4 groove design optimizes bearing load carrying surface area and oil flow to connecting rod bearings
• Increased crush factor enhances bearing retention and stability during operation
• Elimination of flash plating on bearing backs improves heat transfer and maximizes grip in housing
• Increased eccentricity compensates for bore distortion at high RPM and assists hydrodynamic oil film formation
• Enlarged ID chamfers on bearing edges accommodate large fillet radii on performance crankshafts
• Precision manufactured to tight wall tolerances for consistent clearances and reliable fit

ACL Race Series bearings are engineered to withstand high RPM conditions and elevated cylinder pressures, making them suitable for both performance street engines and competition applications. These bearings have proven themselves in NASCAR, NHRA, drag racing, and road racing applications worldwide.