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 lowers 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 78255X

Cup Part Number

 N/A 78571

Bore (d)

 N/A 2.5586 in64.988 mm

O.D. (D)

 N/A 5.7080 in144.983 mm

Width (T)

 N/A 1.4173 in35.999 mm
Dynamic Radial Load Rating - 1M Revs (C1)1 N/A 45600 lbf203000 N
Dynamic Radial Load Rating - 90M Revs (C90) 2 N/A 11800 lbf52600 N
e Factor3 N/A 0.87
K Factor4 N/A 0.67
Y Factor 5 N/A 0.69

Other Dimensions

Weight

 N/A 5.6 lb2.5 Kg

Inner Ring Width (B)

 N/A 1.2962 in32.923 mm

Outer Ring Width (C)

 N/A 0.9058 in23.007 mm
Effective Center Location6 N/A 0.31 in7.9 mm
Max Shaft Fillet Radius7 N/A 0.14 in3.6 mm
Max Housing Fillet Radius8 N/A 0.14 in3.56 mm

Shaft Backing Shoulder Diameter - Frontface (da)

 N/A 3.11 in79 mm

Shaft Backing Shoulder Diameter - Backface (db)

 N/A 3.5 in89 mm

Housing Backing Shoulder Diameter - Frontface (Da)

 N/A 5.22 in132.59 mm

Housing Backing Shoulder Diameter - Backface (Db)

 N/A 4.65 in118.11 mm

Cage Location Relative to Backface (Aa)

 N/A 0.24 in6.1 mm

Cage Location Relative to Frontface (Ab)

 N/A 0.22 in5.6 mm

Ratings

Dynamic Axial Rating - 90M Revs (Ca90)9 N/A 17500 lbf77900 N

Static Radial Load Rating (C0)

 N/A 43400 lbf193000 N

Factors

G1 Factor

 N/A 62.6

G2 Factor

 N/A 19.1
Geometry Factor (Cg)10 N/A 0.0884
  • 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 These factors apply for both inch and metric calculations. Consult your Timken representative for instruction on use.
  • 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 Negative value indicates effective center inside cone backface.
  • 7 These maximum fillet radii will be cleared by the bearing corners.
  • 8 These maximum fillet radii will be cleared by the bearing corners.
  • 9 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.
  • 10 Geometry constant for Lubrication Life Adjustment Factor a3l.