A cylindrical roller bearing carries load through rollers between inner and outer raceways. Its basic rating life uses the bearing's catalog basic dynamic load rating C and the calculated equivalent dynamic bearing load P; for roller bearings, L10 = (C/P)10/3 million revolutions.
Roller Wheel Anti-friction Bearing Interactive Calculator
Calculate ISO-style basic rating life for a roller bearing from catalog dynamic rating C, equivalent dynamic load P and constant speed.
Equation Used
- C is the identified bearing's catalog basic dynamic load rating.
- P is an already calculated constant equivalent dynamic bearing load in the same force units as C.
- Speed is constant and positive.
- Modified-life factors, load spectrum, static safety, minimum load, speed limit, lubrication, contamination, fits, clearance, temperature and misalignment are excluded.
The secondary figure uses the same selected C, P and speed while showing generic cylindrical-roller-bearing topology.
How a cylindrical roller bearing works
Cylindrical rollers circulate between inner and outer raceways while a cage spaces the rolling elements. The rollers provide nominal line contact, making this bearing family well suited to radial load; axial capability and ring separability depend on the specific flange arrangement and bearing designation.
The animation is a topology view with a fixed outer ring and rotating inner ring. Roller spin and cage motion are illustrative rather than a contact-kinematic solution.
What this calculator demonstrates
Enter catalog basic dynamic load rating C, calculated equivalent dynamic bearing load P and constant speed n. The calculator returns ISO-style basic rating life in millions of revolutions and hours, plus C/P and P/C for transparent input checking.
It does not calculate P from radial and axial loads, evaluate static safety, minimum load, speed limits, internal clearance, fits, lubrication, contamination, misalignment, temperature or modified rating life.
Basic rating life for a roller bearing
For roller bearings, p = 10/3. Basic rating life is L10 = (C/P)p million revolutions. At constant speed n in min−1, L10h = 106L10/(60n) hours.
L10 is the life reached or exceeded by 90% of a sufficiently large group of apparently identical bearings before material-fatigue evidence develops. It is not a warranty or a prediction of one bearing's actual service life.
Selected example
For C = 100 kN, P = 50 kN and n = 20 rpm, C/P = 2. The basic rating life is about 10.079 million revolutions, or about 8,399 hours at constant speed.
This example uses P as an already determined equivalent dynamic bearing load. A real selection must use the identified bearing's catalog data and load factors, then check the other applicable limits.
Scope and correction boundary
SKF, Schaeffler and NTN references support the basic life equation and the 10/3 roller-bearing exponent. They also distinguish basic rating life from modified life and actual service life, which depend on lubrication, contamination, installation and other operating conditions.
The removed page supplied universal friction ratios, surface finishes, clearance changes, minimum-load percentage, failure timing and application-specific life ranges without an identified bearing and operating calculation. Those claims are removed.
Questions
Is P just the applied radial force?
Not necessarily. P is the equivalent dynamic bearing load. Its calculation depends on the selected bearing and the actual radial and axial load case.
Does L10 mean every bearing will last that long?
No. It is a population-based basic fatigue-life rating at 90% reliability under the stated idealized inputs.
Why is there no universal minimum-load output?
Minimum-load requirements depend on bearing type, size, speed, lubrication and manufacturer data; a fixed fraction of C is not established by these three inputs.
Does the result include contamination and lubrication?
No. Those require a modified rating-life method and additional identified-bearing data.
Primary technical references
- Schaeffler Technical Pocket Guide — ISO 281 basic rating life, equivalent dynamic load and p = 10/3 for roller bearings.
- SKF Rolling Bearings catalogue — basic and modified rating life, minimum-load checks and operating factors.
- NTN Ball and Roller Bearings catalogue — roller-bearing basic life equations and load terminology.
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