King Engine Bearings MB1337XP0.25-5 XP-Series Main Bearing Set Undersize - 0.25mm

The King Engine Bearings MB1337XP0.25-5 is a high-performance main bearing set from King's legendary XP-Series race bearing line. Engineered for extreme performance applications, this 5-piece main bearing set is sized at 0.25mm undersize to fit reground or undersized crankshafts.

XP-Series Race Technology:

• Enhanced tri-metal copper-lead construction with nickel barrier layer
• Features pMax Black overlay—24% harder than conventional tri-metal race bearings
• Superior load capacity of 17,000 psi in the intermediate layer and 10,200 psi in the overlay
• Bulls Eye Tolerance: Industry-leading wall thickness consistency of ±0.0001 inch
• SecureBond adhesion process for superior stability between layers
• 0.0005 inch metallurgically enhanced and hardened performance overlay

Performance Features:

• Developed for high-load, long-duration racing with steel crankshafts
• Ideal for circle track, drag racing, off-road, and offshore applications
• Half-groove design for uncompromised lower shell load capacity
• Enlarged, chamfered oil holes for improved oil flow
• Narrowed design accommodates large-radius crankshafts
• Advanced geometric features optimize load distribution

0.25mm Undersize Specification: This bearing set is designed for crankshafts that have been ground 0.25mm (0.010 inch) undersize from standard specifications. The additional shell thickness compensates for the reduced crankshaft journal diameter, maintaining proper oil clearance and bearing crush.

King Engine Bearings has been the gold standard in engine bearing manufacturing since 1960, with every bearing manufactured in-house using the highest quality materials and strictest quality control processes. The XP-Series represents King's most advanced race bearing technology for builders who demand maximum reliability under extreme loads.