Bearing Numbers Explained

  • (1) Prefix :
  • (2) Basic Number:
  • (3) Suffix


K Cage with roller elements
L Removable bearing ring
R Ring with roller set
S Roll body of stainless steel
W Stainless steel deep groove ball bearing

*Note: Each bearing company may create their own prefixes. e.g. E2. = SKF Energy Efficient bearings


2 RS Bearing with rubber seal on both sides. RS provides a better seal but more rolling friction than 2Z.
RS Bearing with rubber seal on one side, one side open.
2 Z / ZZ Bearing with a metal seal on both sides.
Z Bearing with a metal seal on one side, one side open.
E Reinforced Design
P2 Highest precision
K Bearing with taper bore

Bearing Numbers

The example at the header shows a 6001 2RS bearing. So what does the 6001 actually mean?
Lets attempt to break it down.


This second number relates the bearing series, which reflects the robustness of the bearing. As you go up the scale below from 9 to 4 the inner and outer race thickness will usually increase along with the ball size, this will be to help cope with extra load.

9 Very thin section
0 Extra light
1 Extra light thrust
2 Light
3 Medium
4 Heavy


The 3rd and 4th digits of the bearing number relate to the bore size of the bearing, numbers 00 to 03 have a designated bore size depending on the number.

00 10mm
01 12mm
02 15mm
03 17mm

While numbers over 03 simply have a bore size which is 5 times that of the 3rd and 4th digit.

This first number relates to the bearing type, as shown in the table below type 6 is a deep grooved roller bearing.

1 Self-Aligning Ball BearingThis kind of ball bearing has a spherical outer race, allowing the axis of the bearing to “wander around”. This is important because misalignment is one of the big causes of bearing failure. Self Aligning Ball Bearing
2 Barrel and Spherical Roller Bearings
3 Tapered Roller BearingDesigned to take large axial loads as well as radial loads. double row angular contact ball bearing
4 Deep Groove Double-Row Ball BearingDesigned for heavy radial loads. Double-Row Ball Bearing
5 Axial Deep Groove Ball BearingIntended for exclusively axial loads. Thrust Ball Bearing
6 Deep Groove Ball Bearing(Single row)Typical ball bearing. Handles light axial loads as well as radial loads. Single-Row Deep Groove Ball Bearing
7 Single-Row Angular Contact BearingSpecific geometry of angular contact bearing raceways and shoulders creates ball contact angles that support higher axial loads Angular contact ball bearing
8 Axial Cylindrical Roller BearingsAxial cylindrical roller bearings comprise axial cylindrical roller and cage assemblies and shaft and housing locating washers.
The bearings have particularly small axial section height, have high load carrying capacity and high rigidity and can support axial forces in one direction.


Axial Cylindrical Roller Bearings
Explore posts in the same categories: MECHANICS

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