Designation Systems / Spherical Roller Bearings
Spherical Roller Bearing Designation System
A spherical roller bearing designation is a basic designation plus optional prefixes and suffixes. For the metric ISO sizes the basic designation is a number: 2 (spherical roller bearing type code) + two digits of dimension series (13, 22, 23, 30, 31, 32, 38, 39, 40, 41, 48, 49) + the two-digit bore code. Two rows of barrel-shaped rollers run on a single spherical outer-ring raceway, so the bearing is self-aligning and combines a very high radial capacity with axial capacity in both directions. Spherical roller bearings are always double row. Most sizes are available with a cylindrical bore or a tapered bore (K = 1:12, K30 = 1:30); because the bore type is written as a suffix, both writings of a size are printed in the same catalogue row and share the same boundary dimensions and basic load ratings. Each manufacturer publishes its own designation system; the sections below put the five brands that catalogue this type side by side.
Anatomy of a Designation
22310 EK
Example shown in SKF style
22310Basic designation — 2 (spherical roller bearing), 23 dimension series (wide), bore code 10 = 50 mm
EInternal designOptimized internal design — higher load-carrying capacity
KBore typeTapered bore, taper 1:12 (K30 would be 1:30)
Bore code (last two digits of the basic designation)
00 = 10 mm bore01 = 12 mm bore02 = 15 mm bore03 = 17 mm bore04 and up = bore (mm) = code × 5/nn = explicit bore after a slash when it is not a multiple of five (22205/20 = 20 mm; 238/500 = 500 mm; 248/1800 = 1800 mm)
SKF
Series & designations
| 213xx / 222xx / 223xx | The narrow ring sections: 13, 22 and 23 dimension series (223 is the widest of the three) |
| 230xx / 231xx / 232xx | Wide series (30, 31, 32) — larger rollers and a higher load rating for the same bore |
| 238xx / 239xx / 240xx / 241xx / 248xx / 249xx | Extra-narrow ring sections (38, 39, 40, 41, 48, 49) for large bores in restricted space |
| 22205/20, 238/500, 248/1800 | Bore written after a slash: the digits are the bore in millimetres (or an explicit bore code) |
| 22205 E / 22205 EK | Both bore types are printed together; the plain writing is the cylindrical bore, the K writing the tapered bore of the same size |
Prefixes
| BS2- | Sealed spherical roller bearing with contact seals on both sides (e.g. BS2-2205-2RS) |
Internal design
| E | Optimized internal design (higher load-carrying capacity) |
| CC, CA | Cage designation — CC: two window-type pressed-steel cages; CA: one-piece machined-brass cage |
Seals & outer-ring features
| 2RS, 2RS5, 2CS5 | Contact seal on both sides (the numeral identifies the seal variant) |
| W33 | Lubrication groove and three holes in the outer ring |
| /VT143 | Factory-filled grease (the number identifies the grease) |
| /VA405 | Design for vibratory machinery |
Cage
| CC | Two window-type pressed-steel cages, one per row |
| CA | One-piece machined-brass cage |
Bore type
| (none) | Cylindrical bore |
| K | Tapered bore, taper 1:12 |
| K30 | Tapered bore, taper 1:30 |
Clearance & accuracy
| C3, C4, C5 | Radial internal clearance greater than Normal (printed against the size in the catalogue) |
NSK
Series & designations
| 213xx / 222xx / 223xx | The narrow ring sections (13, 22, 23 dimension series) |
| 230xx … 241xx | The wide series (30, 31, 32) and the extra-narrow series (39, 40, 41) |
| 22205CE4 / 22205CKE4 | Cylindrical-bore and tapered-bore writings are printed in the same table row with the same d/D/B and ratings |
| 239/500, 240/1120 | Bore written after a slash, in millimetres |
Prefixes
| * | NSKHPS™ high-performance design (printed as an asterisk before the designation): higher load-carrying capacity and limiting speed, dimensionally stable up to 200 °C |
Internal design
| C, CD | Pressed-steel cage designs |
| EA | High-capacity NSKHPS™ design with a pressed-steel cage |
| CA | Machined-brass cage (recommended for applications with vibration or shock) |
Seals & outer-ring features
| E4 | Oil groove and holes in the outer ring |
| W33 | Lubrication groove and holes in the outer ring |
Bore type
| (none) | Cylindrical bore |
| K | Tapered bore, taper 1:12 |
| K30 | Tapered bore, taper 1:30 |
Schaeffler (FAG)
Series & designations
| 213xx … 249xx | The same twelve dimension series as the other brands (13, 22, 23, 30, 31, 32, 38, 39, 40, 41, 48, 49) |
| 22205-E1-XL / 22205-E1-XL-K | The cylindrical-bore and tapered-bore writings of a size share one table row and the same ratings |
| 23320, 23332 … 23344 | Spherical roller bearings for vibratory machinery (two rows of larger rollers); catalogued with a -T41A suffix |
| WS22205-E1-XL-2RSR | Sealed design (WS prefix); the seal makes the bearing wider than the open bearing of the same size, so it is a separate catalogue table |
Prefixes
| WS | Sealed spherical roller bearing (own dimension table; contact seals on both sides) |
Internal design
| -E1 | X-life design — optimized internal geometry, higher load rating and longer life |
| -BE, -BEA | Higher-capacity design (B); -BEA is its X-life version |
Seals & outer-ring features
| -2RSR | Contact seal (NBR) on both sides |
| -2VSR | Sealed design (VSR seal) |
Cage
| -TVPB | Solid plastic cage, window type |
| -M, -MB1 | Machined brass cage (-MB1: one-piece brass cage with central rib) |
| -JPA | Pressed-steel cage (one-piece, for vibratory machinery) |
| -MA1 | Machined brass cage (for vibratory machinery) |
Bore type
| (none) | Cylindrical bore |
| -K | Tapered bore, taper 1:12 |
| -K30 | Tapered bore, taper 1:30 |
Other suffixes
| -XL | X-life bearing (premium design, longer service life) |
| -T41A, -T41D | Heat-treated (dimensionally stabilized) design for vibratory machinery |
NTN
Series & designations
| 213xx / 222xx / 223xx | The narrow ring sections (13, 22, 23 dimension series) |
| 230xx … 241xx | The wide series (30, 31, 32) and the extra-narrow series (39, 40, 41) |
| ＊22205EAW33 / ＊22205EAKW33 | Cylindrical-bore and tapered-bore writings sit in the same table row; the ＊ marks the ULTAGE design |
Prefixes
| ＊ | ULTAGE series — NTN premium spherical roller bearing design |
Internal design
| EA, EM | Internal-design code printed after the bore number |
Seals & outer-ring features
| W33 | Lubrication groove and holes in the outer ring |
| D1 | Printed design suffix of the size (varies with the series) |
Bore type
| (none) | Cylindrical bore |
| K | Tapered bore, taper 1:12 |
| K30 | Tapered bore, taper 1:30 |
Timken
Series & designations
| 213xx … 249xx | The metric dimension series (13, 22, 23, 30, 31, 32, 33, 38, 39, 40, 41, 49) |
| 22206EJ / 22206EM | The cage code is part of the designation: the same size in two cages, each with its own load ratings |
| 230/600YMB, 241/950YMD | Large sizes (outer diameter above 600 mm) use the YM, YMB and YMD cages |
Cage
| EJ | Hardened stamped-steel cage — two independent land-riding cages, one per row (sizes up to 600 mm outside diameter) |
| EM | Precision-machined brass cage, roller-riding finger type (up to 600 mm outside diameter) |
| EMB | Precision-machined brass cage, land-riding finger type (up to 600 mm outside diameter) |
| YMB | Precision-machined brass cage, land-riding finger type (outside diameter above 600 mm) |
| YMD | Precision-machined brass cage, land-riding finger type (outside diameter above 600 mm) |
| W33 | Lubrication groove and three holes in the outer ring (added to the designation) |
Bore type
| (none) | Cylindrical bore — Timken catalogues this type with a cylindrical bore only |
Good to Know
- The type code 2 and the two-digit dimension series lead the basic designation: 213, 222 and 223 are the narrow ring sections, 230/231/232 the wide series and 238/239/240/241/248/249 the extra-narrow ones. The last two digits are the bore code.
- Spherical roller bearings are inherently double row: the two rows of barrel-shaped rollers run on one spherical outer-ring raceway, which is what makes the bearing self-aligning. There is no single-row version of this bearing type.
- The bore type is a suffix, not a different size. The same size is printed twice in one catalogue row — cylindrical bore and tapered bore — and both share the boundary dimensions and basic load ratings: 22205 → SKF 22205 E / 22205 EK, Schaeffler (FAG) 22205-E1-XL / 22205-E1-XL-K, NSK 22205CE4 / 22205CKE4, NTN 22205EAW33 / 22205EAKW33. Timken writes a different cage code instead: 22205EJ.
- Sealed designs have their own dimension table because the seals make the bearing wider than the open bearing of the same size: SKF BS2-2205-2RS (B = 23 mm) or Schaeffler (FAG) WS22205-E1-XL-2RSR against the open 22205 (B = 18 mm). Their published limiting speed is the sealed grease limit, not the open-bearing speed.
- Schaeffler (FAG) -T41A / -T41D bearings are the vibratory-machinery versions of the 223 / 233 sizes: same boundary dimensions as the standard bearing, but heat-treated and often fitted with a JPA steel or MA1 brass cage.
- Timken prints the cage code as part of the designation and the codes carry different load ratings (22206 EJ = 67.4 kN against EM = 64.3 kN), so each code is an orderable bearing in its own right — a designation with EJ, EM, EMB, YMB or YMD is not interchangeable with another code of the same size.
- No extracted spherical roller bearing table carries a cage column, and the catalogues print the same size with several cage options, so this dataset leaves the cage field empty rather than guessing the material from the designation.
- Speed definitions differ between the brands: SKF and Schaeffler (FAG) publish a reference speed plus a limiting speed, NSK publishes a thermal speed rating (oil bath) together with grease, oil and forced-circulation limits, NTN publishes grease / oil limiting speeds, and Timken publishes a thermal reference speed for each lubricant plus a separate limiting speed.
- SKF (Pu), Schaeffler (FAG) (Cur) and NTN (Cu) publish a fatigue load limit; NSK and Timken do not, so no value is shown for those brands.
- Availability of a suffix varies by size — always confirm the exact designation in the manufacturer catalogue you are ordering from.
Disclaimer: Data on this page is compiled from publicly available online sources for reference only, and not every model appears in a manufacturer's published catalog. Values may differ between sources and editions — always verify against the manufacturer's current documentation before design or purchase.Full disclaimer →
