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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This is the most basic and most widely used type of tapered roller bearing. It consists of two main separable parts: the cone (inner ring) assembly and the cup (outer ring). It is typically mounted in opposing pairs on a shaft.
Unit of Measure

Other Dimensions

Weight

 N/A 5.9 Kg13.1 lb

Inner Ring Width (B)

 N/A 43 mm1.6929 in
Max Shaft Fillet Radius1 N/A 4.060 mm0.16 in

Shaft Backing Shoulder Diameter - Frontface (da)

 N/A 117 mm4.61 in

Shaft Backing Shoulder Diameter - Backface (db)

 N/A 128 mm5.04 in

Cage Location Relative to Frontface (Ab) 

 N/A 6.6 mm0.26 in

Cage Location Relative to Backface (Aa)

 N/A 6.9 mm0.27 in
Effective Center Location2 N/A 13.2 mm0.52 in

Key Dimensions

Series

 N/A 31318M

Cone Part Number

 N/A X31318M

Bore (d)

 N/A 90 mm3.5433 in
Dynamic Radial Load Rating - 90M Revs (C90) 3 N/A 84000 N18900 lbf
Dynamic Radial Load Rating - 1M Revs (C1) 4 N/A 324000 N72800 lbf
C1 - Dynamic Radial Rating (Two-Row, 1 million revolutions)5 N/A 564000 N127000 lbf
Dynamic Radial Load Rating 2-Row - 90M Revs (C90-2row) 6 N/A 146000 N32900 lbf
K Factor 7 N/A 0.71

Ratings

Static Radial Load Rating (C0)

 N/A 421000 N94600 lbf
Ca90 - Dynamic Thrust Rating (90 million revolutions)8 N/A 119000 N26700 lbf

Factors

G1 Factor

 N/A 169.3

G2 Factor

 N/A 37.1
Geometry Factor (Cg)9 N/A 0.114
  • 1 These maximum fillet radii will be cleared by the bearing corners.
  • 2 Negative value indicates effective center inside cone backface.
  • 3 Based on 90 x 106 revolutions L10 life, for The Timken Company life calculation method. C90 and Ca90 are radial and thrust values.
  • 4 Based on 1 x 106 revolutions L10 life, for the ISO life calculation method.
  • 5 Based on 1 x 106 revolutions L10 life, for the ISO life calculation method.
  • 6 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.
  • 7 These factors apply for both inch and metric calculations. Consult your Timken representative for instruction on use.
  • 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 Geometry constant for Lubrication Life Adjustment Factor a3l.