NSK standard cylindrical roller bearings use pressed, machined, or molded cages. The basic load ratings listed in the NSK bearing size chart are based on the cage classification as shown below.
| Series | Pressed stell cages (W) | Machined brass cages (M) | Molded polyamide cages (T) |
|---|---|---|---|
| NU10** | - | 1005 -- 10/500 | - |
| N2** | 204 -- 230 | 232 -- 264 | - |
| NU2** | 214 -- 230 | 232 --264 | - |
| NU2**E | 205E -- 213E | 214E -- 240E | 204E |
| NU22** | 2204 -- 2230 | 2232 -- 2252 | - |
| NU22**E | - | 2222E --2240E | 2204E -- 2220E |
| N3** | 304 -- 330 | 332 -352 | - |
| NU3** | 312 -- 330 | 332 -- 352 | - |
| NU3**E | 312 -- 330 | 332 -- 352 | - |
| NU23** | 2304 -- 2320 | 2322 -- 2340 | - |
| NU23**E | - | 2322E -- 2340E | 2304E -- 2320E |
| NU4** | 405 -- 416 | 417 -- 430 | - |
For a given NSK bearing number, if the type of cage is not the standard one, the number of rollers may vary; in such a case, the load rating will differ from the one listed in the NSK bearing tables.
