What does the +0.25mm size mean for these bearings?

The +0.25mm designation indicates that these bearings are intended for a crankshaft that has been machined down by 0.25mm. This is a common practice during engine rebuilds to achieve the correct oil clearance when the crankshaft journals have been ground undersize.

What is the advantage of the lead-free composite material?

The lead-free composite material is an environmentally safe option that is ideal for medium-load engines. It helps ensure proper bearing function while meeting environmental standards.

Does this bearing set come with all the necessary hardware for installation?

This product is a main bearing set and typically includes only the main bearings themselves. It is recommended to consult the manufacturer's installation guide or a professional mechanic to determine if additional hardware or sealants are required for your specific engine rebuild.

Specifications

Brand: King Engine Bearings
Part #: MB7776SI0.25
UPC: 611500587276

King Engine Bearings BMW N55B30A/N53B30A/N52B30A Main Bearing Set - Size +0.25mm

Name: King Engine Bearings BMW N55B30A/N53B30A/N52B30A Main Bearing Set - Size +0.25mm
Brand: King Engine Bearings
SKU: king-engine-bearings-king-engine-bearings-bmw-n55b30a-n53b30a-n52b30a-main-beari-t14-45775
Price: 85.16 USD
Availability: InStock

$85.16

In Stock

King Engine Bearings BMW N55B30A/N53B30A/N52B30A Main Bearing Set - Size +0.25mm. Lead-free composite ideal for medium-load engines.

Key Features

This main bearing set is +0.25mm undersize, intended for use with a crankshaft machined to that specification.
Features a lead-free, environmentally safe composite material suitable for medium-load engines.
Constructed with a bi-metal aluminum material for good thermal conductivity and wear resistance.
Designed for BMW N55B30A, N53B30A, and N52B30A engine applications.
King Engine Bearings has been a specialist in bearing manufacturing since 1960.

⚠️ CA WARNING: This product can expose you to chemicals known to the State of California to cause cancer and/or birth defects or other reproductive harm. Learn more

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About this part

Product Details

Built with a lead-free, environmentally safe composite material, this main bearing set from King Engine Bearings is specifically designed for medium-load engines. These bearings are a +0.25mm undersize, meaning they are intended for crankshafts that have been machined down by that amount during a rebuild. This is a critical component for the health of your BMW's engine, ensuring smooth rotation of the crankshaft within the engine block.

King Engine Bearings has specialized in bearing technology since 1960, focusing on supplying well-built bearings for various applications. This particular set utilizes a bi-metal aluminum material, which offers good thermal conductivity and wear resistance. When rebuilding or repairing an engine like the BMW N55B30A, N53B30A, or N52B30A, using bearings that are precisely sized and made from appropriate materials is key to achieving proper oil clearance and long-term durability. This set is designed to fit a wide range of BMW models, from the 1 Series M to the X5 and Z4, ensuring a proper fit for many common applications.