Important suffixes for roller bearings

Here you can find a list of roller bearing suffixes sorted from A-Z.
Suffixes only determine the specific properties of a bearing type: for example, which seal, which bearing air, which cage and much more. Bearing type and main dimensions are not specified by suffixes but by the base character.
Example: the type "S6205 2RS.C3" has the prefix S, the base character 6205, two suffixes 2RS and C3: a corrosion-resistant (S) single-row deep groove ball bearing (6) with the dimensions 25-52-15 mm (205), sealed on both sides (2RS) and higher radial bearing air (C3).


Internal construction of bearing has been changed. External dimensions of bearing remain the same. The letters have individual meanings depending on the type of bearing and manufacturer. They are not standardised. For this reason you should look up the meanings for each different type of bearing in the manufacturer's catalogue.

A (single-row angular ball bearing SKF): Contact angle 30°
B (single-row angular ball bearing SKF): Contact angle 40°
E (many types): changed internal construction, higher load factor

Suffix Description


Y-bearing SKF: Standard seals with centrifugal disc on both sides


Y-bearing SKF: Multiple seals on both sides

2RS1 (SKF)

Sealing ring on both sides of the bearing.
Seal type: contact seals on both sides

The bearing is filled with grease and normally maintenance-free. For use if moisture and splash water cannot be excluded. The seals are in elastomer materials (mostly MBR), and are mostly reinforced with a sheet steel disc.

The additional letter (if present) (e.g. 1 or R) behind 2RS designates the specific 2RS version.
Improved 2RS seals are 2RSH, 2RS2. Please refer here.
Depending on the bearing type, the sealing lips contact the
  • shell surface of the inner ring shoulder (SKF 6...: if dimension d1 is noted in the product table)
  • embedding in inner ring shoulder (SKF 6...: if dimension d2 is noted in the product table)
  • Sliding surface at/on inner ring raceway
  • Sliding service in outer ring raceway.
You can find details on the version in the bearing datasheet on the bearing manufacturer's website.

Important note for ordering: If "RS" is engraved on both sides of the bearing, you must order the double-sided versions "2RS" or "2RS1", "2RSR" or "2RSH".
If you order the "RS" version (also: RSR, RS1, RS2, RSH) in the shop you will receive a bearing which is sealed on one side and is open on the other side, and is also not pre-greased.

2RS2 (NKE)



Improved 2RS plastic seal, on both sides of the bearing.
Seal type: dual lip seal. Therefore improved sealing effect compared with 2RS1, 2RSR, 2RS.
The sealing lips contact the bearing inner ring.


Low-friction, steel plate-reinforced sealing rings in NBR (plastic) on both sides of the bearing.


Seals of type LFS (Low Friction Seal) on both sides of the bearing. Seal type: axial sealing lip, radial sealing lip in groove, contact-free on bearing inner ring.



ZZ (misc.)

Non-contact cover disc, generally in sheet steel, on both (2Z or ZZ) sides of the bearing. Use for when soiling hazard is low and lack of friction is decisive.
Seal type: Gap bearing, made with long sealing gap on the inner ring shoulder or labyrinth seal above embedding on inner ring shoulder. 2Z bearings are ready-filled with grease ex-works. See also ZZ.

Important note for ordering: If "Z" is engraved on both sides of the bearing, you must order the double-sided versions "2Z" or "ZZ".
If you order the "Z" version (also: ZR) in the shop you will receive a bearing which is covered on one side and is open on the other side, and is also not pre-greased.


The ABEC scale determines the tolerance classes for the production of ball bearings. A higher number is equivalent to a lower manufacturing tolerance for the bearing. 

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



Needle bearings(INA): Lubrication hole provided in outer ring (or bush)

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

Radial bearing air normal, in unloaded condition. This suffix letter is normally not written since it is standard. For "normal" fittings and "normal" operating conditions. For deep groove ball bearings between 18 and 30 mm bore, the standard bearing air is 5 to 20 µm. You can find bearing air tables in the bearing catalogue for the relevant bearing model.

Bearing air is more precisely specified for special applications:
CNH: Bearing air is in the top half of air class
CNL: Bearing air is in the bottom half of air class
CNR: Bearing air is restricted in acc. w. "paired rings”.


Air group: Radial bearing air less than normal


Air group: Radial bearing air is larger than normal C3 is available for many types from stock.

Application e.g. with strongly heated bearing for which sufficient play during operation is necessary due to thermal expansion. In the case of smaller deep groove ball bearings, C3 means approx. 1/100 mm higher bearing air.


Air group: Radial bearing air even larger than C3 If not available in C4, bearings can possibly be re-ground to C4.


Single-row angular ball bearing: low axial air before fitting


Single-row angular ball bearing: normal axial air before fitting


Single-row angular ball bearing: more axial air before fitting


Tapered roller bearing with tolerances in acc. w. ISO Tolerance Class 6X


incl. changed ring grooves in outer ring


Bearing set: Two single-row bearings, prepared for paired installation. The following letters A,B,C,CA,CB,CC,C,GA,GB,G identify axial bearing air or pretensioning before installation.
Please refer to roller bearing catalogue or special catalogue for precision bearings for details.


NSK designation for sealing ring contacting inner ring on both sides. See 2RS.


Cylinder roller bearings in modern, optimised construction. The inner ring and cylinder rollers were modified in particular.
Note: in very old cylinder roller bearings the suffix E is missing. If you are fitting modern bearings, please compare the old/new connection dimensions.


Cylinder roller bearing: modern model (E) polyamide cage (TVP)., increased bearing air (C3)


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


SKF lubricating grease ID. Please refer to the SKF catalogue/website for a description of the numerous lubricants


SKF lubricating grease on polyurea basis, -30 to +150°C, standard filling quantity


Housing disc for an axial cylinder roller bearing. The internal diameter is slightly larger than the shaft diameter. See also WS.. (shaft disc)


Snap cage in sheet steel, pressed and hardened.


Lubricating grease for high temperatures -20 to +130°C (SKF). If a two-digit number follows HT, then it is a grease which deviates from standard. For details see SKF website.


Y-bearing SKF: Bearing components are in stainless steel. The bearing is filled with a food-compatible lubricating grease.


Sheet steel cage. The suffix "J" is only stated if the sheet steel cage is not the standard cage for this bearing type. Example: Cylinder roller bearing.


Tapered roller bearing SKF: Sheet steel cage in structural variation 2


Tapered roller bearing SKF: two ready-fitted adapted, single-row bearing in X arrangement.


Bearing has inner ring with conical bore. Cone 1:12. Not suitable for fitting to cylindrical shaft! The bearing is fitted to a cylindrical shaft using clamping sleeves (e.g. order H.. clamping sleeves together) or to a conically turned shaft without clamping sleeves.


As K, cone 1:30


Solid cage in brass (brass plate see: Y)


as with M, cage is outer ring-guided


as with M, cage is inner ring-guided


Solid window cage in brass


SKF lithium soap grease for operating temperatures between -30°C and +110°C


1. Ring groove in outer ring jacket, for dimensions see roller bearing catalogue

2. for INA tensioning bearing housings: Cast housing with groove recess for protective caps


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


as N with groove and circlip already placed in outer ring groove


Sealing ring on one side of the bearing

P0, PN

Normal tolerance. Not normally written in the suffix.
Tolerances to inner ring, outer ring, bearing width and width of rings are specified in the so-called tolerance classes. This is intended primarily to ensure interchangeability and equivalents of bearings.
See also P6, P5, P4 and P4S.


Tolerance class: Bearing with extremely high dimensional, shape and running precision, more precise than P5.


Tolerance class: Bearing with especially high dimensional, shape and running precision, more precise than P6.


Tolerance class: Bearing with increased dimensional, shape and running precision. More precise than normal tolerance. Tolerance value: see roller bearing catalogue or standards


Sealing ring on both sides of the bearing


Supporting rollers: crowned shell surface on outer ring (standard). For cylindrical shell surface: see suffix X.


Prefix letter: Inner or outer bearing ring … with roller set


Sealing ring only on one side of bearing, see 2RS for seal on both sides


Self-aligning roller bearing: Lubrication bore in circumferential outer ring groove. See also W33 for FAG, NKE bearings


Bearing rings heat-treated, up to +150°C


Bearing rings heat-treated, up to +200°C


Bearing rings heat-treated, up to +250°C


Bearing rings heat-treated, up to: +300°C


Deep groove ball bearing type 6.. in stainless steel


Tensioning bearings: Bore has hexagonal shape (bore is not cylindrical)


General: Special quality regulations (works standard). The digits following SQ state the specification.
SQ77: current-insulated bearing.


FAG self-aligning roller bearing for oscillating loading. For applications see also VA405 (SKF)


Window cage in phenolic resin with fabric inlay. Suitable for extremely high rotation speeds.


Cage in polyamide


Snap cage in polyamide, ball-guided. Inexpensive, therefore often standard cage. See also TV


Cage made from polyether ether ketone (PEEK) suitable for special requirements. See SKF catalogue (5000 G, Jan. 2004, p. 142)


Solid window cage in polyamide (TV) model window cage (P), structural variation 2 or 3


Solid window cage in polyamide (TV), model snap cage (H). For details see roller bearing catalogue.


Solid window cage in polyamide, guided on inner ring


Slight pretensioning in installed condition. Pretensioning is the force which results from negative operating play or negative bearing air in the installed condition.


Medium pretensioning in installed condition


High pretensioning in installed condition


Full-complement bearing (increased number of roller bodies in bearing, without cage)

VA201 VA208 VA228

SKF bearing for extremely high temperatures (e.g. furnace trolleys). See SKF catalogue


SKF self-aligning roller bearing for vibrating machines, e.g. oscillating sieve in quarries, suitable for higher loadings and acceleration As standard for SKF with bearing air C4, with circumferential groove, with 3 lubrication bores. With cylindrical or conical (suffix K) bore. See also T41A (manufacturer FAG)


Shaft seal in fluoride-rubber basis (FPM/FKM), more temperature-resistant than standard material NBR (NBR has suffix BA)


Contact-free plastic seal on both sides, similar to 2RSL (SKF)


Bearing made from "stainless steel". At, "stainless steel" bearings are labelled with the prefix letter S, "stainless steel" bearings from manufacturer FAG are additionally labelled with suffix W203B.


Self-aligning roller bearing: Circumferential groove and 3 lubrication bores in outer ring. Older suffix, common for SKF bearings. See also S


Shaft disc for axial cylinder roller bearing. See also GS.. (housing disc)


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


a) Cylindrical shell surface in outer ring for supporting and cam rollers, if normal variation with crowned outer ring
b) parts, whose dimensions have been adapted to international standards (e.g. various tapered roller bearings)


Cage made of sheet brass (see also M and J for other materials)


Cover disc only on one side of the bearing

Order bearing covered on both sides in version "2Z".


double-row needle bearing


Sealing ring on both sides of the bearing


This technical information is based on carefully researched information from the relevant manufacturer, it is intended for initial information and is provided without liability. You can find datasheets in the roller bearing catalogues on the manufacturer websites, and also in standards DIN 623 Part 1 (roller bearing principles: designation, identification)