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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

Specifications

Series

28000

Cone Part Number

28118

Cup Part Number

28317

Design Unit

Inch

Cage Material

Stamped Steel

Dimensions

d - Bore

1 3/16 in30.163 mm

D - Cup Outer Diameter

3.1510 in80.035 mm

B - Cone Width

0.8244 in20.940 mm

C - Cup Width

0.6250 in15.875 mm

T - Bearing Width

0.8439 in21.435 mm

Abutment and Fillet Dimensions

R - Cone Backface "To Clear" Radius1 0.06 in1.5 mm
r - Cup Backface "To Clear" Radius2 0.06 in1.52 mm

da - Cone Frontface Backing Diameter

1.48 in37.5 mm

db - Cone Backface Backing Diameter

1.57 in40 mm

Da - Cup Frontface Backing Diameter

2.91 in73.90 mm

Db - Cup Backface Backing Diameter

2.72 in69.09 mm

Ab - Cage-Cone Frontface Clearance

0.07 in1.8 mm

Aa - Cage-Cone Backface Clearance

0.06 in1.5 mm
a - Effective Center Location3 -0.19 in-4.8 mm

Basic Load Ratings

C90 - Dynamic Radial Rating (90 million revolutions)4 4390 lbf19500 N
C1 - Dynamic Radial Rating (1 million revolutions)5 16900 lbf75200 N

C0 - Static Radial Rating

15500 lbf68900 N
Ca90 - Dynamic Thrust Rating (90 million revolutions)6 3020 lbf13400 N

Factors

K - Factor7 1.45
e - ISO Factor8 0.4
Y - ISO Factor9 1.49

G1 - Heat Generation Factor (Roller-Raceway)

20.7

G2 - Heat Generation Factor (Rib-Roller End)

12.5
Cg - Geometry Factor10 0.0709
  • 1 These maximum fillet radii will be cleared by the bearing corners.
  • 2 These maximum fillet radii will be cleared by the bearing corners.
  • 3 Negative value indicates effective center inside cone backface.
  • 4 Based on 90 x 106 revolutions L10 life, for The Timken Company life calculation method. C90 and Ca90 are radial and thrust values.
  • 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 These factors apply for both inch and metric calculations. Consult your Timken representative for instruction on use.
  • 9 These factors apply for both inch and metric calculations. Consult your Timken representative for instruction on use.
  • 10 Geometry constant for Lubrication Life Adjustment Factor a3l.