The complete designation for SKF needle roller and track runner bearings consists of a basic designation (refer to SKF bearing designation) , which identifies SKF bearing type and size, as well as supplementary designations. These designation suffixes identify design features that differ from the standard design. Where several supplementary designations are used to identify a particular bearing, they are always written in a specific order. The supplementary designations listed below are not exhaustive, but include those most commonly used.
| Suffix | Description |
|---|---|
| A | NUTR design support rollers and NUKR design cam followers with an improved crowned profile of the outer ring running surface |
| AS.. | Lubrication hole(s) in the outer ring, a figure following indicates the number of holes |
| ASR.. | Annular groove and lubrication hole(s) in the outer ring, a figure following indicates the number of holes |
| B | KR design cam followers with a crowned profile of the outer ring running surface and a recessed hexagon on both ends of the stud |
| BF | Needle roller with flat ends |
| C2 | Bearing internal clearance smaller than Normal |
| C3 | Bearing internal clearance greater than Normal |
| CN | Bearing internal clearance Normal, only used together with an additional letter (H, L, M, P) that identifies a reduced or displaced clearance range |
| C4 | Bearing internal clearance greater than C3 |
| D | Deviating or modified internal design with the same boundary dimensions. Generally dropped after a certain changeover period, but may have the significance to bound to the particular bearing design/series |
| DS | Single split needle roller and cage assembly |
| EGS | Inner ring with a non-directionally ground raceway |
| G2 | Needle roller in accordance with ISO 3096:1996 Grade 2 |
| H.. | SKF needle roller bearing without an inner ring, with reduced inside diameter (under rollers) tolerance, followed by tolerance limits in μm, e.g. H+27+20 |
| IS.. | Needle roller bearing with one or more lubricating holes in the inner ring, a figure following indicates the number of holes |
| ISR.. | Needle roller bearing with an annular groove and one or more lubricating holes in the inner ring, a figure following indicates the number of holes |
| M../M.. | Diameter tolerance of needle rollers, e.g. M2/M4 indicates diameter tolerance –2 to –4 µm |
| N/M.. | Diameter tolerance of needle rollers, e.g. N/M2 indicates diameter tolerance 0 to –2 µm |
| P5 | Dimensional and running accuracies to ISO tolerance class 5 |
| P6 | Dimensional and running accuracies to ISO tolerance class 6 |
| P6CNR | P6 + CNR |
| P62 | P6 + C2 |
| P63 | P6 + C3 |
| PPA |
1. NATR or NATV design support rollers with a polyamide 66 axial sliding and sealing ring on both sides. Improved crowned profile of the outer ring running surface. 2. KR design cam followers have the same features as listed above. Sizes 16 and 19 have one slot in the head of the stud as standard. Size 22 and larger have a recessed hexagon on both ends. |
| PPSKA |
KR design cam followers, sizes 16 and 19, with a polyamide 66 axial sliding and sealing ring on both sides, improved crowned profile of the outer ring running surface and a hexagon recessed into the head of the stud. These cannot be relubricated. |
| PPXA | Cam followers with PPA features except for the outer ring running surface, which has a cylindrical profile |
| RS | Contact seal of acrylonitrile-butadiene rubber (NBR) with or without sheet steel reinforcement on one side of the bearing |
| .2RS | RS contact seal on both sides of the bearing |
| ..S | Matched bearings for an equal distribution of the radial load. The figure preceding indicates the number of bearings, e.g. NK 50/25 TN/2S |
| S | Radial shaft seals with low cross sectional height, rubber material is metal cased, e.g. G 6x12x2 S |
| 2S | Two matched bearings for an equal distribution of radial load (refer to S, the figure preceding the S indicates the number of bearings) |
| S0 | Bearing rings or washers dimensionally stabilized for use at operating temperatures up to 150 °C |
| S1 | Bearing rings or washers dimensionally stabilized for use at operating temperatures up to 200 °C |
| S2 | Bearing rings or washers dimensionally stabilized for use at operating temperatures up to 250 °C |
| S3 | Bearing rings or washers dimensionally stabilized for use at operating temperatures up to 300 °C |
| SM.. | Special grease, two figures following identify the grease |
| /SORT.. | Tolerance grade of needle rollers of a needle roller and cage assembly, the figures following give the actual limits in μm, e.g. /SORT-2-4 |
| TN | Injection moulded cage of glass fibre reinforced polyamide 66 |
| VGS | Inner ring with a pre-ground raceway and a machining allowance |
| VG052 | Single split cage of polyethersulfone (PES) |
| X | Track runner bearings with a cylindrical (flat) profile of the outer ring running surface |
| XA | NUKR .. A and NUKRE .. A design cam followers with a cylindrical (flat) profile of the outer ring running surface |
| Z | Combined needle roller bearings, axial bearing with a cover over the outside diameter without lubrication holes. Filled at the factory with a high-quality lithium base NLGI 2 grease. |
| ZW | Double row needle roller and cage assembly |
| .2ZL | Support rollers with a lamellar seal on both sides |
