Bearing Life & Safety Factor Calculator

Bearing Specifications
Bearing Size SR09  
Bore Diameter (d) 0.04 in
Outer Diameter (D) 0.125 in
Outer Width (Bo) 40.0000 mm
Inner Width (Bi) 40.0000 mm
Width (B) 0.0469 in
Flange Diameter (Df) 40.0000 mm
Flange Width (Bf) 40.0000 mm
Dynamic Load Rating (Cr) 20 lbs
Static Load Rating (Cor) 5 lbs
Max Speed (Grease) 130,000 rpm
Max Speed (Oil) 150,000 rpm
Ball Quantity 6  
Ball Diameter (Dw) 0.025 in
Material Martensitic Stainless Steel  
Enter Input Parameters
Radial Load, Fr lbs
Axial Load, Fa lbs
Rotating Speed, n rpm
L10 Basic Rating Life
Note: 90% Reliability
1,003 Hours
Select values below to calculate the Adjusted Service Life
a1 Life Reliability
Default: 90%
Yields L10 Service Life
a2 Special Bearing
a3 Operating Temp.
a4 Elastohydrodynamic
(EHD) Conditions

Service Life
Lna = a1 × a2 × a3 × a4 × L10

Safety Factor, fs

Normal Operation: 1.0 Shock Load: 1.5 Silent, High Accuracy: 2.0


It should be understood that it is not possible to ascribe a given fatigue life to a solitary bearing application.  The L10 Basic Rating Life is the estimated fatigue life of a large population of such bearings under the specified loading.  It is assumed that the bearings have normal internal radial clearance, they are handled & mounted properly, and there is no misalignment, no excessive heat, or contamination in the bearings.  The load ratings, formulae, adjustment factors, table values, and other technical data contained in AST Bearings’ catalogs and website are intended to provide guidance in making bearing selections, but may not be applicable in all operating conditions.  The results shown use calculation methods based on ABMA Standard 9 and ISO 281 for basic radial & axial combination loading.  Customers must ensure that an experienced and knowledgeable design engineer performs a comprehensive analysis for their specific applications.  AST Bearings assumes no liability for final bearing selections and specifications.  In the case of a more complex loading situation, please contact AST Engineering for further assistance.