Why Replace Rod Bearings?

Why Replace Rod Bearings?

For any enthusiast or racer who has spent enough time on forums or around other BMW owners, it comes as no surprise that spun rod bearings are the Achilles heel of many BMW Engines, especially the S54, S65, and S85. While it may be easy to dismiss, 'my engine is low mileage,' ' this car doesn't see any track use,' etc, we have seen catastrophic rod bearing failure on low mileage commuter cars that followed BMW maintenance procedures religiously. The truth is, it doesn't matter your driving style or vehicle application, BMW rod bearings are a ticking bomb, with the consequences including severe crankshaft damage, engine seizure, or complete engine failure. 

Ensuring the longevity of you BMW engine is as simple as replacing the factory rod bearings with Calico Coated bearings, featuring increased clearances. But first, let's talk about why:

Tight OEM Clearances

The OEM rod bearing clearances, or the space between the crank journals and bearings, are incredibly tight. This makes it difficult for oil to flow through the space in between. Oil flow through this space is crucial to provide a layer of lubrication and cushioning to prevent the two metals from rubbing. 

The Consequences

As oil flow is compromised between the crank journal and the bearing, the two metals will rub, causing shavings to be released into the engine. These shavings will cause serious damage to the engine as they flow throughout the oiling system, which is irreversible. If the bearing and journal seize completely, the damage will be irreversible, causing complete engine failure. 

Calico Coatings

5150 AutoSport High Performance Rod Bearings feature Calico's Specialized Dry Film Lubricant Coating, which is designed to reduce friction and abrasive wear. In other words, thanks to the Calico Coating, these bearings not only compensate for oil starvation, but they are also a better, safer bearing for cold starts and the extreme conditions of high performance engines. 

Calico Coating offers a better, safer bearing for cold starts, oil starvation, and the extreme conditions of high performance engines.

Increased Clearances

5150 AutoSport High Performance Rod Bearings also feature greater clearances than factory bearings, one of the known weak points of OEM bearings. These clearances allow for greater oil flow throughout the rotating assembly, ensuring that each bearing is properly lubricated. 

ARP Rod Bolts

Each 5150 AutoSport High Performance Rod Bearing Kit also features ARP Rod Bolts. These bolts are specifically designed and manufactured by ARP to the exact length and thread of each BMW connecting rod, making them a stronger, higher quality replacement for OEM rod bolts. 

Essential for securing connecting rods to the crankshaft, ARP Rod Bolts offer exceptional strength, durability, and fatigue resistance. Made from specialized ARP2000 or Custom Age 625+ materials, these bolts are better equipped for the extreme forces and high loads of BMW engines.


There is no guaranteed way to test if your engine has damaged bearings, but for many modern BMW engines, the odds that your engine will experience rod bearing failure within its lifetime is very likely. Whether your application is a tame grocery getter or a fully built track monster, the cost to replace your engine bearings is significantly cheaper than replacing the engine or a complete engine overhaul.

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