ACL Race Series Main Bearings – Honda Civic Type R (FK8/FL5) – K20C1

Overview

The ACL Race Series Main Bearings (Part Nos: 5M1985H-STD, 5M1985HX-STD, 5M1985H-.025) are engineered for high-performance and motorsport applications. Manufactured using advanced tri-metal construction, these bearings deliver exceptional fatigue resistance, superior oil film strength, and precise tolerances to support high-RPM and high-load environments. Whether you're building a street-driven turbo engine or a full track-spec setup, ACL Race Bearings are trusted by professional builders worldwide.

Key Features

• High-performance tri-metal construction for superior durability under extreme loads
• Hardened steel backs for improved shell support and bearing retention
• Reduced overlay thickness for enhanced fatigue resistance at high RPM
• 3/4 groove design to optimise oil flow across the bearing surface
• Increased crush and tight wall tolerances ensure consistent oil clearance
• Eliminated flash plating for improved heat transfer and housing grip
• Enlarged chamfers to accommodate large fillet crankshafts

Available Sizes

Technical Specifications

• Tunnel Diameter: 59.000 – 59.020mm
• Shaft Diameter: 54.980 – 55.000mm
• Maximum Wall Thickness: 2.002mm
• Maximum Bearing Length: 20mm
• Configuration: Upper & Lower Shells
• Weight: Approx. 280g

Vehicle Compatibility

• Engine-specific compatibility varies – confirm sizing with crankshaft and block measurements