What does a bearing's load rating indicate?

A bearing's load rating is fundamentally a measure of how much load the bearing can support while ensuring reliability and longevity during its use. This rating considers not just the weight it can hold but also the duration over which that load can be applied without resulting in premature wear or failure.

When a bearing runs under load, factors such as heat generation, lubrication adequacy, and material fatigue come into play; all of which can affect the bearing's operational life. The load rating helps engineers select the appropriate bearing for specific applications in machinery to ensure that it can handle the expected loads over its intended lifespan without failing.

The other options, while related to bearings, do not accurately capture the essence of the load rating. The maximum weight before failure suggests a singular moment of load capacity without regard for duration, while operational efficiency at various speeds and ideal temperature ranges pertain to performance characteristics rather than load-bearing capabilities.