Bearing Type

Designed in

Bearing Part Number

Property Value - Full or Partial Part Number

Advanced Criteria

Dimension Min Max Unit

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Item Value Unit

Bearing Class

Nominal Values

Dimension Value Unit
Outer Diameter

Tolerance Results

Dimension Max Min Unit

To perform calculation, the following are required:

  • Select a lubricant
  • Operating Speed > 0
  • Operating Temperature must be within 70°F - 250°F and 20°C - 120°C

Dynamic Load Ratings

Property Value Unit

Select a lubricant

Temperature Value Unit


Property Value Unit
Speed rpm
Radial Load
Axial Load
Operating Temperature

Apply Life Adjustment Factors


Item Value Unit
Viscosity at Operating Temperature
L10 Life Hours
Lubrication Factor (a3l)
Low Load Factor (a3p)
Adjusted Life L10a3 = L10 * a3l * a3p Hours

Timken Engineering Manual

Bearing testing has shown that effective lubrication and light loads can significantly improve the bearing performance over what is predicted using just the applied loads and the load ratings, while poor lubrication can be detrimental. The Timken Technology Center scientists and engineers have quantified these effects into adjustment factors, a3L for lubrication effectiveness and a3P for light load adjustments, which can be used to enhance the life estimates for your bearing system. For more information, follow the link to page 50 in the Timken Engineering Manual, where the adjustment factors are explained in more detail.

IMPORTANT NOTE: The accuracy of this technical review is dependent upon the validity and completeness of information supplied to Timken. Actual product performance is affected by many factors beyond the control of Timken. Therefore, the suitability and feasibility of all designs and product selection should be validated by you. For the above reasons, this review is submitted solely to provide you, a customer of Timken or its parent or affiliates, with data to assist you in your design. No warranty, expressed or implied, including any warranty of fitness for a particular purpose, is made by Timken by the submission of this review. Timken products are sold subject to Limited Warranty which is set forth in Timken’s terms and conditions of sale.

Operating Speed (rpm)

View the technical paper:
Bearing Dynamics and Sound

Element Value Comments
BPFI - Ball or Roller Pass Frequency - Inner
BPFO - Ball or Roller Pass Frequency - Outer
BSF - Ball or Roller Spin Frequency
FTFI - Fundamental Train Frequency - Inner Rotation
FTFO - Fundamental Train Frequency - Outer Rotation
Frequencies Resulting From Component Irregularities Hz
f0 or f1 - Eccentricity or Out-Of-Round Rotating Member rps
f2 - Ball or Roller Irregularity = BSF * rps * 2
Ball or Roller Spin Frequency = BSF * rps
f3 - Inner Race Irregularity = BPFI * rps
f4 - Outer Race Irregularity = BPFO * rps
f5 - Ball or Roller Size Variations - Rotating Inner = FTFI * rps
f6 - Ball or Roller Size Variations - Rotating Outer = FTFO * rps
Bearing Relative Component Speeds (Revs/Sec)
Inner / Outer or Outer / Inner
Cage / Outer
Other frequencies that may occur include the following harmonics and modulations of Fundamental and Harmonic frequencies.
( i = Harmonic Index of the carrier frequency i.e. i = 1,2,3,4,...
  k = Harmonic Index of the modulating frequency i.e. k = 0,1,2,3,... )
  • f1 * i
  • f4 * i
  • f5 * i
  • f6 * i
  • f4 * i + f1 * k or f4 * i - f1 * k
  • f2 * i + f5 * k or f2 * i - f5 * k
  • f2 * i + f6 * k or f2 * i - f6 * k

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