The Timken Company
The Timken Company
4500 Mt Pleasant St. NW
N. Canton, OH 44720
Phone: (234) 262-3000
E-Mail: CustomerCAD@timken.com • Web site: www.timken.com
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Key Features

  • Available in single, double and multi-row configurations, as well as proprietary sizes
  • Designed in collaboration with OE engineers to design, engineer and test bearings for premium performance in many applications
  • Power dense designs allow for heavier loads and can help extend bearing life
  • Optimized internal geometry lower torque and operating temperatures to extend lubrication system life
  • Can be designed to withstand high-corrosive, high-temperature and vacuum or low-lubrication environments with proprietary enhancements
Unit of Measure

Key Dimensions

Cone Part Number

 N/A 78255D

Cup Part Number

 N/A 78537

Bore (d)

 N/A 2.5586 in64.988 mm

O.D. (D)

 N/A 5.375 in136.525 mm

Width (T)

 N/A 2.6020 in66.091 mm
Dynamic Radial Load Rating - 1M Revs (C1) 1 N/A 66900 lbf298000 N
Dynamic Radial Load Rating - 90M Revs (C90) 2 N/A 9970 lbf44300 N
Dynamic Radial Load Rating 2-Row - 90M Revs (C90-2row) 3 N/A 17400 lbf77200 N
e Factor4 N/A 0.87
K Factor5 N/A 0.67

Other Dimensions

Inner Ring Width (B)

 N/A 2.5980 in65.989 mm
Max Shaft Fillet Radius6 N/A 0.06 in1.5 mm
Max Housing Fillet Radius7 N/A 0.13 in3.3 mm

Shaft Backing Shoulder Diameter - Frontface (da)

 N/A 3.11 in78.95 mm

Housing Backing Shoulder Diameter - Backface (Db)

 N/A 4.53 in115.06 mm

Cage Location Relative to Frontface (Ab) 

 N/A 0.08 in2 mm

Outer Ring Width (C)

 N/A 0.9260 in23.520 mm

Series

 N/A 78000

Weight

 N/A 1.5 lb0.70 Kg

Ratings

Dynamic Axial Rating - 90M Revs (Ca90) 8 N/A 14800 lbf65700 N

Factors

Y1 Factor 9 N/A 0.78
Y2 Factor 10 N/A 1.16
Geometry Factor (Cg) 11 N/A 0.0884

Spacer

Note

 N/A Spacer shows standard nominal .01 radii, actual bearing may vary
  • 1 Based on 1 x 106 revolutions L10 life, for the ISO life calculation method.
  • 2 Based on 90 x 106 revolutions L10 life, for The Timken Company life calculation method. C90 and Ca90 are radial and thrust values.
  • 3 Based on 90 x 106 revolutions L10 life, for The Timken Company life calculation method. C90 and Ca90 are radial and thrust values for a single-row, C90(2) is the two-row radial value.
  • 4 These factors apply for both inch and metric calculations. Consult your Timken representative for instruction on use.
  • 5 These factors apply for both inch and metric calculations. Consult your Timken representative for instruction on use.
  • 6 These maximum fillet radii will be cleared by the bearing corners.
  • 7 These maximum fillet radii will be cleared by the bearing corners.
  • 8 Based on 90 x 106 revolutions L10 life, for The Timken Company life calculation method. C90 and Ca90 are radial and thrust values for a single-row, C90(2) is the two-row radial value.
  • 9 These factors apply for both inch and metric calculations. Consult your Timken representative for instruction on use.
  • 10 These factors apply for both inch and metric calculations. Consult your Timken representative for instruction on use.
  • 11 Geometry constant for Lubrication Life Adjustment Factor a3l.