Important suffixes for rolling bearings

Below you will find an A-Z list of rolling bearing suffixes.
The suffixes only specify the specific properties of the type of bearings: for example, the type of seal, the clearance, the cage and more. The type of bearing and main dimensions are not specified by suffixes, but by the base character.
For example, the "S6205 2RS.C3" version has the prefix S, the base character 6205, the two suffixes 2RS and C3: this stands for corrosion-resistant (S), single-row deep-groove ball bearings (6) with the dimensions 25-52-15 mm (205), sealed on both sides (2RS) and higher radial clearance (C3).


The internal design of the bearing has been changed. The external dimensions of the bearing remain the same. The characters have particular meanings depending on the type of bearing and the manufacturer. They are not standardised. You should therefore look up the meaning in the manufacturer’s catalogue for the relevant type of bearing.

A (SKF single-row angular contact ball bearings): 30° contact angle
B (SKF single-row angular contact ball bearings): 40° contact angle
E (many types): modified internal design, higher load rating

Suffix Description


SKF Y-bearings: Standard seals with flinger shields on both sides


SKF Y-bearings: Multiple seals on both sides

2RS1 (SKF)

Sealing washer on both sides of the bearing.
Type of seal: seal rubbing on the inner ring

The bearing is filled with grease and generally does not require maintenance. For use when moisture and splashing water cannot be ruled out. The seals are made of elastomer materials (mostly NBR) and usually reinforced with a sheet steel washer.

An additional character (e.g. 1 or R) after the 2RS identifies the specific 2RS version.
Improved 2RS seals include 2RSH, 2RS2. See below.
Depending on the type of bearing, the sealing lip is in contact with the
  • outside surface of the inner ring shoulder (SKF 6...: when size d1 is indicated in the product table)
  • groove in the inner ring shoulder (SKF 6...: when size d2 is indicated in the product table)
  • Sliding surface in/on the inner ring raceway
  • Sliding surface in the outer ring raceway
You can find details on the design in the bearings data sheet on the relevant manufacturer’s website.

Important order information: When “RS” is stamped on both sides of the bearing, you must order the "2RS" or "2RS1", "2RSR" or "2RSH" double-sided version.
If you order the “RS” design (including RSR, RS1, RS2, RSH) in the store, you will receive a bearing that is sealed on one side and open on the other side and which will not have been greased at the factory.

2RS2 (NKE)



Improved 2RS plastic seal on both sides of the bearing.
Type of seal: double-lip seal. It thus has improved sealing effect in comparison to the 2RS1, 2RSR and 2RS versions.
The seal lips are in contact with the bearing inner ring


Low-friction, steel-reinforced sealing washers made of NBR (plastic) on both sides of the bearing.


LFS (Low Friction Seal) seals on both sides of the bearing. Type of seal: axial sealing lip, radial sealing lip in the groove, is not in contact with the bearing inner ring



ZZ (other)

Non-rubbing sealing shield, usually sheet steel on both (2Z or ZZ) sides of the bearing. Used when there is a low risk of contamination and when it is crucial for there to be no friction.
Type of seal: Gap seal, designed with a long sealing gap on the inner ring shoulder or labyrinth seal over the recess on the inner ring shoulder. 2Z bearings are filled with grease at the factory ready for assembly. See also ZZ.

Important order information: If “Z” is imprinted on both sides of the bearing, you must order the double-sided “2Z” or “ZZ” version.
If you order the “Z” design (including ZR), you will receive a bearing that is covered on one side and open on the other and has not been greased at the factory.


The ABEC scale specifies tolerance classes for manufacturing ball bearings. A higher number means that the bearing has a lower manufacturing tolerance. 

ABEC scale   DIN620
ABEC 1   P0
ABEC 3   P6
ABEC 5   P5
ABEC 7   P4
ABEC 9   P2



Needle roller bearings (INA): Lubrication hole in the outer ring (or sheet metal sleeve) available

CN (DIN 620-4:2004)
C0 (old)

Normal radial clearance, in unloaded state. This suffix is usually not included, as it is the standard. For “normal” clearances and “normal” operating conditions. For deep-groove ball bearings with a bore of 18 – 30 mm, the standard bearing clearance is 5 to 20 µm. You can find bearing clearance tables in the bearing catalogue for the relevant bearing design.

For special applications, the bearing clearance is specified in more detail:
CNH: Clearance is in the upper half of the clearance class
CNL: Clearance is in the lower half of the clearance class
CNR: Clearance is restricted according to “paired rings”


Clearance group: Radial clearance is lower than normal


Clearance group: Radial clearance is greater than normal. C3 is available from stock for many types.

It is used, for example, in highly heated bearings for which sufficient clearance is required due to thermal expansion. For small deep-groove ball bearings, C3 refers to a 1/100 mm greater clearance.


Clearance group: Radial internal clearance even greater than C3. If not available in C4, bearings can be ground down to C4 if necessary.


Single-row angular contact ball bearings: low axial clearance prior to installation


Single-row angular contact ball bearings: normal axial clearance prior to installation


Single-row angular contact ball bearings: greater axial clearance prior to installation


Tapered roller bearings with tolerances corresponding to ISO tolerance class 6X


Modified snap ring grooves in the outer ring among other things


Bearing set: Two single-row bearings, prepared for installation in pairs. The characters A,B,C,CA,CB,CC,C,GA,GB,G indicate axial clearance or preload prior to installation.
See the rolling bearing catalogue or special catalogue for precision bearings for details.


NSK designation for a double-sided contact seal on the inner ring. See 2RS.


Cylindrical roller bearings with a modern, streamlined design. In particular, the inner ring and cylindrical rollers have been modified.
Note: very old cylindrical roller bearings lack the “E” suffix. If you are installing modern bearings, please compare the old/new connecting dimensions.


Cylindrical roller bearings: modern design (E), polyamide cage (TVP), increased clearance (C3)


Solid steel cage.
(sheet steel cage: see J).


SKF lubricating grease designation. See the SKF catalogue/website for a description of the various lubricants


SKF polyurea lubricating grease, −30 to +150 °C, standard filling amount


Cylindrical roller thrust bearing housing washer. The inner diameter is slightly wider than the shaft diameter. See also WS.. (Shaft washer)


Sheet steel snap cage, pressed and hardened.


Lubricating grease for high temperatures −20 bis +130 °C (SKF). If there is a two-digit number after HT, it is a non-standard grease. See the SKF website for details.


SKF Y-bearings: Bearing parts are made from stainless steel. The bearing is filled with food-grade lubricating grease.


Sheet steel cage. The J suffix is only included if the sheet steel cage is not the standard cage for the bearing version. Example: cylindrical roller bearings.


SKF tapered roller bearings: Sheet steel cage design version 2


SKF tapered roller bearing set: two matching single-row bearings in an X-arrangement ready for installation.


Bearing has an inner ring with a tapered bore. 1:12 taper. Not suitable for installation on cylindrical shafts! The bearing is installed with an adapter sleeve (e.g. order H..-adapter sleeve as well) on a cylindrical shaft or without an adapter sleeve on a tapered shaft.


Same as K, 1:30 taper


Solid brass cage (sheet brass, see: Y)


Same as M, cage is guided on the outer ring


Same as M, cage is guided on the inner ring


Solid brass window cage


SKF lithium soap grease for operating temperatures from −30 °C to +110 °C


1. Snap ring groove in the outer ring; see rolling bearing catalogue for details

2. for INA radial insert ball bearings: Cast iron housing with undercut slot for end caps


Two retaining slots on one side of the outer ring (common with QJ2.. four-point bearings)


Same as N with slot and a snap ring already inserted in the outer ring slot


Sealing ring on one side of the bearing

P0, PN

Normal tolerance. Usually not included in the suffix.
The tolerance of the inner ring and outer ring, the bearing width and the width of the rings are specified in the so-called tolerance classes. This is primarily to ensure the interchangeability and uniformity of bearings.
See also P6, P5, P4 and P4S.


Tolerance class: Bearings with very high dimensional, shape and running accuracy are more precise than P5.


Tolerance class: Bearings with particularly high dimensional, shape and running accuracy; more precise than P6


Tolerance class: Bearings with increased dimensional, shape and running accuracy. More precise than normal tolerance. Tolerance values: see bearing catalogue or standards


Sealing ring on both sides of the bearing.


Yoke type track rollers: crowned outer ring surface (standard). For cylindrical outer surfaces: see suffix X


Initial suffix character: Bearing inner or outer ring .. with roller set


Sealing washer only on one side of the bearing; see 2RS for seals on both sides


Spherical roller bearings: Lubrication holes in the surrounding outer ring groove. See also W33 for FAG and NKE bearings


Heat-treated bearing rings, up to +150°C


Heat-treated bearing rings, up to +200°C


Heat-treated bearing rings, up to +250°C


Heat-treated bearing rings, up to +300°C


Type 6 deep-groove ball bearings made of stainless steel


Radial insert ball bearings: Bore has a hexagon socket (bore is not cylindrical!)


General: special quality specification (factory standard). The following characters after SQ indicate the specification.
SQ77: electrically insulated bearings.


FAG spherical roller bearings for oscillating loads. See also VA405 (SKF) for applications


Phenolic resin window cage with fabric inserts. Suitable for very high speeds.


Polyamide cage


Polyamide snap cage, ball-guided. Cost effective, therefore often the standard cage. See also TV


Polyetheretherketone (PEEK) cage, suitable for special requirements. See SKF catalogue (5000 G, Jan 2004, p. 142)


Solid polyamide window cage (TV), window cage design (P), design version 2 or 3


Solid polyamide window cage (TV), snap cage design (H). See the rolling bearing catalogue for details


Solid polyamide window cage, guided by the inner ring


Light preload when installed. Preload is the force that arises from negative operating clearance or negative clearance when installed.


Medium preload when installed.


High preload when installed.


Full complement bearings (increased number of rolling elements in the bearing, no cage)

VA201 VA208 VA228

SKF bearings for extremely high temperatures (e.g. oven bearings) See SKF catalogue


SKF spherical roller bearings for vibratory machinery, e.g. shaking screens in quarries, suitable for higher loads and acceleration. C4 clearance as standard for SKF, with circumferential groove, with 3 lubricating holes. With cylindrical or tapered (suffix K) bore. See also T41A (manufacturer: FAG)


Fluorine rubber (FPM/FKM) shaft seals, greater temperature resistance than standard NBR (NBR has the suffix BA)


Non-contact plastic seal on both sides, as with 2RSL (SKF)


“Stainless steel” bearings. At, “stainless” bearings are identified with the initial suffix S; FAG “stainless” bearings also have the suffix W203B.


Spherical roller bearings: circumferential groove and 3 lubrication holes in the outer ring. Older suffix; common with SKF bearings. See also S


Cylindrical roller thrust bearing shaft washer. See also GS.. (housing washer)


Lubricating grease for temperature range −40 to +160 °C (SKF).


a) Cylindrical outer surface for yoke type track rollers and stud type track rollers; with crowned outer ring if normal version.
b) parts with dimensions adapted to international standards (e.g. various tapered roller bearings)


Sheet brass cage (for other materials see M and J)


Sealing shield on just one side of the bearing

Order bearings that are covered on both sides, version "2Z".


Double-row needle bearings


Sealing shield on both sides of the bearing: see 2Z.


This technical information is based on the careful research of the relevant manufacturers’ information; it is meant to provide basic information and is subject to change. You can find data sheets in the rolling bearing catalogues on the manufacturer’s websites as well as in DIN standard 623 Part 1 (rolling bearings: identification, marking)