Maintenance & Reliability worked example

Bearing Life with basic rating life of 10,000 hr: a worked example

This worked example runs the bearing life numbers for a tougher week than the baseline: basic rating life of 10,000 hr instead of the typical 20,000 hr. Estimate bearing life from basic rating life and adjustment factors for speed, load, and reliability.

The inputs for this scenario

  • Basic rating life: 10,000 hr (the input this scenario stresses; the baseline uses 20,000)
  • Speed factor: 1 x (held at the documented default)
  • Load factor: 0.75 x (held at the documented default)
  • Reliability factor: 0.9 x (held at the documented default)

Working through the calculation

  • The calculation starts from the formula this tool documents: Base adjusted bearing life = basic rating life × speed factor × load factor.
  • Estimated Bearing Life works out to 6,750 hr at these inputs, and this is the headline figure for the scenario.
  • Base Life Before Reliability Factor works out to 7,500 hr at these inputs.
  • Reliability Factor works out to 0.9 x at these inputs.
  • Rating Life Times Speed Factor works out to 10,000 value at these inputs.

How this compares with the baseline

  • Against the tool's baseline example, where basic rating life sits at 20,000 hr and the headline result is 13,500 hr, this scenario comes in 50% below the baseline at 6,750 hr.
  • Use it when setting PM intervals or evaluating whether an operating change in speed or load will shorten bearing service life. A result at this level usually justifies acting on the stressed input before touching anything else, because every other figure in the table is downstream of it.

Results at a glance

  • Estimated Bearing Life: 6,750 hr (headline result)
  • Base Life Before Reliability Factor: 7,500 hr
  • Reliability Factor: 0.9 x
  • Rating Life Times Speed Factor: 10,000 value

Run it with your numbers

  • To rerun this with your own numbers, open the live Bearing Life calculator, set basic rating life to your actual value, and adjust the remaining inputs to match your operation.

Last reviewed 2026-05-12.