Montage of Timken Bearing Products
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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

 N/A 38800

Cone Part Number

 N/A 38886

Cup Part Number

 N/A 38820

Design Unit

 N/A Inch

Cage Material

 N/A Stamped Steel

Dimensions

d - Bore

 N/A 10 1/2 in266.7 mm

D - Cup Outer Diameter

 N/A 12.8125 in325.438 mm

B - Cone Width

 N/A 1.3177 in33.470 mm

C - Cup Width

 N/A 1.0000 in25.400 mm

T - Bearing Width

 N/A 1.1614 in29.500 mm

Abutment and Fillet Dimensions

R - Cone Backface "To Clear" Radius1 N/A 0.06 in1.520 mm
r - Cup Backface "To Clear" Radius2 N/A 0.06 in1.52 mm

da - Cone Frontface Backing Diameter

 N/A 10.83 in275 mm

db - Cone Backface Backing Diameter

 N/A 10.91 in277 mm

Da - Cup Frontface Backing Diameter

 N/A 12.48 in316.99 mm

Db - Cup Backface Backing Diameter

 N/A 12.28 in311.91 mm

Ab - Cage-Cone Frontface Clearance

 N/A 0.01 in0.3 mm

Aa - Cage-Cone Backface Clearance

 N/A -0.01 in-0.3 mm
a - Effective Center Location3 N/A 0.77 in19.6 mm

Basic Load Ratings

C90 - Dynamic Radial Rating (90 million revolutions)4 N/A 13200 lbf58700 N
C1 - Dynamic Radial Rating (1 million revolutions)5 N/A 50900 lbf227000 N

C0 - Static Radial Rating

 N/A 118000 lbf527000 N
Ca90 - Dynamic Thrust Rating (90 million revolutions)6 N/A 8260 lbf36800 N

Factors

K - Factor7 N/A 1.6
e - ISO Factor8 N/A 0.37
Y - ISO Factor9 N/A 1.64

G1 - Heat Generation Factor (Roller-Raceway)

 N/A 993.2

G2 - Heat Generation Factor (Rib-Roller End)

 N/A 480.2
Cg - Geometry Factor10 N/A 0.166
  • 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.