Maintenance & Reliability worked example

Bearing Life with basic rating life of 50,000 hr: a worked example

What does the result look like when basic rating life reaches 50,000 hr? The full calculation is worked below with real intermediate numbers. Use it when comparing bearing selections, duty changes, or the effect of reliability targets on expected life.

The inputs for this scenario

  • Basic rating life: 50,000 hr (raised for this scenario; the documented default is 20,000)
  • Speed factor: 1 x (unchanged)
  • Load factor: 0.75 x (unchanged)
  • Reliability factor: 0.9 x (unchanged)

Working through the calculation

  • Applying the documented formula (Base adjusted bearing life = basic rating life × speed factor × load factor) to the inputs above produces each figure below.
  • At this operating point the engine returns 33,750 hr for estimated bearing life, the number this scenario is built around.
  • At this operating point the engine returns 37,500 hr for base life before reliability factor.
  • At this operating point the engine returns 0.9 x for reliability factor.
  • At this operating point the engine returns 50,000 value for rating life times speed factor.

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 150% above the baseline at 33,750 hr.
  • A figure at this level is achievable when basic rating life is genuinely sustained, not just peaked for a shift. It's a multiplicative adjustment model, not a full ISO 281 life calculation — it omits lubrication, contamination, and temperature, which often dominate real bearing failures.

Results at a glance

  • Estimated Bearing Life: 33,750 hr (headline result)
  • Base Life Before Reliability Factor: 37,500 hr
  • Reliability Factor: 0.9 x
  • Rating Life Times Speed Factor: 50,000 value

Run it with your numbers

  • Every input above is editable in the live Bearing Life calculator, which recalculates instantly and can be shared with the inputs intact.

Last reviewed 2026-05-12.