The pin diameter is made larger to distribute the load over a greater surface area, reducing the load per unit area on the bearing. This also increases the relative sliding speed between the pin and the bearing, aiding lubrication.

The bearing shells are lined with layers of materials designed for specific purposes:

• Flash Layer (2-5 µm): 100% tin to prevent oxidation and act as a dry lubricant during initial operation.
• Overlayer (20-30 µm): An alloy of 85% lead, 10% tin, and 2% copper to provide good embedability and conformity with the pin's surface geometry.
• Nickel Dam (3 µm): A pure nickel layer offering corrosion resistance to the main bearing layer.
• Main Layer (0.5 mm): Made of aluminium (60%) and tin (40%) for high strength and anti-friction properties.
• Steel Backing: Provides the structural strength needed to support the bearing shell.

The crosshead bearing features a machined wedge to assist hydrodynamic lubrication, creating an oil film that supports the load during operation. The crosshead pin is manufactured with a high surface finish to reduce metal-to-metal contact in the boundary lubrication region, further minimising edge loading.

• The 120° arc of special surface geometry on the lower shell ensures that the load from the connecting rod is spread over a larger area of the bearing surface. This prevents point or edge loading that would cause high pressures and potential failure.
• The axial and transverse oil grooves, combined with the carefully designed geometry, facilitate the establishment of a hydrodynamic oil film. This film separates the moving surfaces, significantly reducing friction and wear. The oil wedge design further helps in establishing a stable lubricating film.
• The soft overlayer in the tri-metal bearing allows the bearing surface to conform to the shape of the crosshead pin, ensuring good contact and consistent lubrication across the entire contact area.
• The use of a tri-metal bearing material ensures wear resistance, corrosion protection, and good embedability for debris.
• A larger pin diameter increases the contact area, thus reducing pressure per unit area. The smooth surface finish helps further reduce friction.

For large two-stroke marine diesel engines (MAN B&W ME-C):

• Top End Bearing Clearance (Crosshead): 0.25 mm to 0.6 mm
• Bottom end bearing clearance (Crankpin bearing): 0.4 mm to 0.8 mm.

These values depend on the engine size and design specifications