Menu
Batch CAD Cart (0) ▾
  • Cart is empty
  1. Click Here for Batch Download
Request Information Add to CAD Cart
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 78000C

Cone Part Number

 N/A 78248C

Design Units

 N/A Imperial

Cage Type

 N/A Stamped Steel
C1 - Dynamic Radial Rating (Two-Row, 1 million revolutions)1 N/A 92600 lbf412000 N
C90(2) - Dynamic Radial Rating (Two-Row, 90 million revolutions)2 N/A 24000 lbf107000 N

Dimensions

d - Cone Bore

 N/A 2 1/2 in63.500 mm

B - Cone Width

 N/A 1.3085 in33.236 mm

Abutment and Fillet Dimensions

R - Cone Backface "To Clear" Radius3 N/A 0.03 in0.800 mm

da - Cone Frontface Backing Diameter

 N/A 3.03 in77 mm

db - Cone Backface Backing Diameter

 N/A 3.62 in92 mm

Ab - Cage-Cone Frontface Clearance

 N/A 0.21 in5.3 mm

Aa - Cage-Cone Backface Clearance

 N/A 0.22 in5.6 mm
a - Effective Center Location4 N/A 0.33 in8.4 mm

Basic Load Ratings

C90 - Dynamic Radial Rating (90 million revolutions)5 N/A 13800 lbf61300 N
C1 - Dynamic Radial Rating (1 million revolutions)6 N/A 53200 lbf237000 N

C0 - Static Radial Rating

 N/A 52600 lbf234000 N
Ca90 - Dynamic Thrust Rating (90 million revolutions)7 N/A 20400 lbf90900 N

Factors

K - Factor8 N/A 0.67

G1 - Heat Generation Factor (Roller-Raceway)

 N/A 71.3

G2 - Heat Generation Factor (Rib-Roller End)

 N/A 17.6
Cg - Geometry Factor9 N/A 0.0926
  • 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 for a single-row, C90(2) is the two-row radial value.
  • 3 These maximum fillet radii will be cleared by the bearing corners.
  • 4 Negative value indicates effective center inside cone backface.
  • 5 Based on 90 x 106 revolutions L10 life, for The Timken Company life calculation method. C90 and Ca90 are radial and thrust values.
  • 6 Based on 1 x 106 revolutions L10 life, for the ISO life calculation method.
  • 7 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.
  • 8 These factors apply for both inch and metric calculations. Consult your Timken representative for instruction on use.
  • 9 Geometry constant for Lubrication Life Adjustment Factor a3l.
By clicking Submit, you consent to the personal information you provide being used in the manner as described in our Privacy Notice, including access to that information by Timken personnel who may be located outside your home country. In addition, you agree that the CAD drawings are for your personal, one-time use only, and that you will not modify or create any compilation or derivative work using the CAD drawings or distribute or display the CAD drawings on any website or other media.