Designation system

The designations of most SKF rolling bearings follow a system that may consist of a basic designation with or without one or more prefixes and/or suffixes (→ Basic bearing designation system).
Examples and the applicable options for single row cylindrical roller bearings are given below.
Basic bearing designation system


NU 10/750 ECN2MA/HB1whereNU 10/750 =
EC =
N2 =
MA =
HB1 =

Angle ring
HJ 212 ECwhereHJ 212 =
EC =

Test Designation 1Prefixes
LSeparate inner or outer ring of a separable bearing
Inner or outer ring with roller and cage assembly of a separable bearing

Test Designation 2Basic designation
Listed in table 1 or drawing number identification
CRLInch bearing
Inch bearing
HJAngle ring
Bearing size for inch bearings




(/8) 1 in. (25,4 mm) bore diameter

(/8) 5 in. (127 mm) bore diameter

Catalogue image - Test Designation 3Suffixes - Internal design
ADeviating or modified internal design
ECOptimized internal design incorporating more and/or larger rollers and with modified roller end / flange contact

Test Designation 4Suffixes - External design (seals, snap ring groove, etc.)
Tapered bore, taper 1:12
NSnap ring groove in the outer ring
NRSnap ring groove in the outer ring, with associated snap ring
N1One locating slot (notch) in one outer ring side face
N2Two locating slots (notches) in one outer ring side face, 180° apart

Catalogue image - Test Designation 5Suffixes - Cage design
Pin-type steel cage, pierced rollers
JStamped steel cage, roller centred
Machined light alloy cage, roller centred
Machined light alloy cage, outer ring centred
Machined light alloy cage, inner ring centred
Machined light alloy cage, window-type, inner or outer ring centred (depending on bearing design)
Machined brass cage, roller centred
MA(S)Machined brass cage, outer ring centred. The S indicates a lubrication groove in the guiding surface.
MBMachined brass cage, inner ring centred
MLMachined brass cage, window-type, inner or outer ring centred (depending on bearing design)
MPMachined brass cage, window-type, inner or outer ring centred (depending on bearing size)
MRMachined brass cage, window-type, roller centred
PGlass fibre reinforced PA66 cage, roller centred
PAGlass fibre reinforced PA66 cage, outer ring centred
PHGlass fibre reinforced PEEK cage, roller centred
PHAGlass fibre reinforced PEEK cage, outer ring centred

Catalogue image - Test Designation 6.1Suffixes - Materials, heat treatment
HA1Case-hardened inner and outer rings
HA2Case-hardened outer ring
HA3Case-hardened inner ring
Bainite-hardened inner and outer rings
HB3Bainite-hardened inner ring
HN1Inner and outer rings with special surface heat treatment

Test Designation 6.2Suffixes - Accuracy, clearance, preload, quiet running
CNNormal radial internal clearance; only used together with an additional letter that identifies a reduced or displaced clearance range
  • H = Reduced clearance range corresponding to the upper half of the actual clearance range
  • L = Reduced clearance range corresponding to the lower half of the actual clearance range
  • M = Reduced clearance range corresponding to the middle half of the actual clearance range
The above letters are also used together with the clearance classes C2, C3, C4 and C5, e.g. C2H.
C2Radial internal clearance smaller than Normal
C3Radial internal clearance greater than Normal
C4Radial internal clearance greater than C3
C5Radial internal clearance greater than C4

Catalogue image - Test Designation 6.3Suffixes - Bearing sets, matched bearings
DRSet of two matched bearings
TRSet of three matched bearings
QRSet of four matched bearings

Test Designation 6.4Suffixes - Stabilization
S1Bearing rings heat stabilized for operating temperatures ≤ 200 °C (390 °F)
S2Bearing rings heat stabilized for operating temperatures ≤ 250 °C (480 °F)

Test Designation 6.5Suffixes - Lubrication
W33Annular groove and three lubrication holes in the outer ring

Test Designation 6.6Suffixes - Other variants
SKF Explorer bearing, used only when same-sized conventional and SKF Explorer bearings are available
Bearing for railway vehicle traction motors
VA305VA301 + special inspection routines
VA350Bearing for railway axleboxes
VA380Bearing for railway axleboxes in accordance with EN 12080, class 1
VA3091VA301 + external surfaces of the outer ring are coated with aluminium oxide
Bearing with special wear-resistant raceways for applications in heavily contaminated environments
VE901Modified internal design
VQ015Inner ring with crowned raceway for increased permissible misalignment
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