Life modification
Reliability, lubrication, contamination, and fatigue limit alter adjusted life.
Engineering
Bearing Safety Factor Calculator
Calculate C/P, basic L10 life, C0/P0 static safety, and life margin against an entered requirement.
BEARING LIFE AND STATIC SAFETY
Keep fatigue life and static indentation risk as separate gates
Dynamic rating C and static rating C0 describe different limits. The page calculates basic rating life and static safety separately and requires both checks.
Dynamic capacity ratio C/P-
Basic L10 life (million rev)-
Static safety factor C0/P0-
Life margin (million rev)-
Combined screening status-
ENGINEERING DECISION VIEW
Compare dynamic life and static risk on separate tracks
A high L10 cannot compensate for inadequate static safety, and vice versa.
| Check | Rating / numerator | Load / exponent | Result | Decision |
|---|
LIVE CALCULATION PROCESS
Formula, substitution, and reconciliation
L10 = (C/P)^p million revolutions; s0 = C0/P0
C/P is raised to the entered exponent for basic rating life. C0/P0 is a separate static-deformation screen. Neither substitutes for adjusted life or application assessment.
HOW TO USE
Screen one selected rolling bearing
- Copy C and C0 for the exact bearing.
- Derive P and P0 under the applicable load factors.
- Choose the correct exponent and required basic life.
- Review both gates, then complete modified-life and application checks.
- Keep the exact bearing designation, catalog revision, P and P0 derivations, duty spectrum, and shock event with the separate life and static decisions.
SUBJECT FUNDAMENTALS
What the two ratings mean
- Dynamic rating C
- Rating used by the basic fatigue-life model.
- Equivalent dynamic load P
- Constant load with the modeled fatigue effect of actual duty.
- Basic L10 life
- 90%-reliability population life under the basic model.
- Static rating C0
- Rating tied to specified permanent contact deformation.
- Equivalent static load P0
- Load representing the static effect of the actual condition.
- Life exponent
- Power governing the nonlinear C/P relationship.
CALCULATION METHOD
Apply rating ratios without mixing meanings
L10 = (C/P)^p million revolutions; s0 = C0/P0
C/P is raised to the entered exponent for basic rating life. C0/P0 is a separate static-deformation screen. Neither substitutes for adjusted life or application assessment.
DEFAULT CASE AUDIT TRAIL
Symbols, units, substitution, and independent check
| Symbol | Meaning | Unit |
|---|---|---|
| C | Basic dynamic load rating | kN |
| P | Equivalent dynamic bearing load | kN |
| p | Life exponent for the bearing type | dimensionless |
| L10 | Basic rating life | million revolutions |
| C0 | Basic static load rating | kN |
| P0 | Equivalent static bearing load | kN |
Default values
- C = 96 kN, P = 32 kN, and p = 3.
- C0 = 72 kN, P0 = 38 kN, and required L10 = 20 million revolutions.
Unit conversion
- Rating and load share kN, so C/P and C0/P0 are dimensionless. The basic-life equation reports million revolutions directly.
Numerical substitution
- Dynamic ratio C/P = 96 / 32 = 3.000.
- L10 = 3^3 = 27.000 million revolutions.
- Life margin = 27 - 20 = 7.000 million revolutions.
- Static factor s0 = 72 / 38 = 1.895.
Named intermediate results
- Dynamic capacity ratio: 3.000.
- Basic L10 life: 27.000 million revolutions.
- Static safety factor: 1.895.
Independent check:Taking the cube root of 27 returns C/P = 3, while multiplying P0 by s0 returns C0 = 72 kN; life and static checks remain separate and both pass the page-stated baseline.
DEEPER ANALYSIS
What changes an application decision
Duty spectrum
Variable load needs damage-equivalent treatment; simple average load can mislead.
Static events
Shock, standstill vibration, transport, and assembly may govern P0.
WORKED DECISION CASES
Two selection screens
Conveyor jam
Basic life passes but jam-event C0/P0 fails, so static loading drives redesign.
Fan comparison
A higher C improves L10, but speed, minimum load, fit, and lubrication still need review.
Bearing rating terminology
- Rating life
- Statistical fatigue-life measure.
- Reliability
- Probability a population reaches a stated life.
- Fatigue load limit
- Parameter used in modified-life assessment.
- Static safety factor
- C0 divided by P0.
- Permanent deformation
- Residual contact change under high load.
- Load spectrum
- Sequence and duration of loads and speeds.
EVIDENCE AND DATA LINEAGE
Retain exact identity, ratings, and load derivations
Keep manufacturer revision, designation, C, C0, bearing type, exponent, P/P0 calculations, duty, reliability, shocks, lubrication, fit, clearance, and unrounded results.
LIMITS AND EXCLUSIONS
What the basic rating screen excludes
- No adjusted life, variable duty, lubrication, contamination, fit, clearance, preload, speed, or thermal analysis is included.
- The page does not derive P/P0 or validate ratings and exponent.
- A pass does not establish lubrication life, temperature, noise, cage behavior, or installation quality.
RELIABLE SOURCES
References for the method and its boundaries
FREQUENTLY ASKED QUESTIONS
Questions about L10 and static safety
Why million revolutions?
That is the base unit of the ISO rating-life equation.
Is p=3 always correct?
No; verify bearing type. Roller bearings generally use another exponent.
Does L10 predict one bearing’s exact failure?
No; it is a statistical population measure.
Is static factor 1 always enough?
No; applications may require more for shock, noise, or precision.
Can the factors be added?
No; they address different mechanisms.
Does this include contamination?
No; use the modified-life method.
RELATED CALCULATORS
Continue the engineering review
Bearing Sensitivity Calculator
Quantify nonlinear life loss when load or effective rating changes.
Bearing Efficiency Calculator
Estimate friction loss without treating efficiency as evidence of fatigue life.
IMPORTANT NOTE
Complete the manufacturer selection procedure
Basic life and static safety are only two gates. Use the current standard, exact manufacturer data, full duty, and qualified review.