NSK bearing designation system
An NSK bearing number is made up of a prefix, basic designation and suffix. The basic designation tells you the bearing type, diameter/width series and bore size. Prefixes and suffixes describe cages, seals, internal clearance, tolerance and special features.
Basic designation of NSK bearing
The basic designation combines the bearing series code and the bore code. The table below shows the most common NSK metric bearing series.
| Bearing type | Series symbols |
| Deep groove ball bearing (single row) | 68, 69, 60, 62, 63 |
| Angular contact ball bearing (single row) | 79, 70, 72, 73 |
| Self-aligning ball bearing | 12, 13, 22, 23 |
| Cylindrical roller bearing (single row) | NU, NJ, NUP, N, NF |
| Cylindrical roller bearing (double row) | NN, NNU |
| Needle roller bearing | NA48, NA49, NA59, NA69 |
| Tapered roller bearing | 302, 303, 320, 322, 323, 329, 330, 331, 332 |
| Spherical roller bearing | 213, 222, 223, 230, 231, 232 |
| Thrust ball bearing | 511, 512, 513, 514, 522, 523, 524 |
| Spherical thrust roller bearing | 292, 293, 294 |
Bore code
For bore diameters from 10 mm to 480 mm the bore code is the bore diameter divided by 5. Special codes apply for small bores: 00 = 10 mm, 01 = 12 mm, 02 = 15 mm, 03 = 17 mm. Bores smaller than 10 mm or larger than 480 mm are stated directly in the designation.
Common NSK suffixes
| Suffix | Meaning |
| Z / ZZ | Pressed steel shield, one or both sides |
| V / VV | Non-contact rubber seal, one or both sides |
| DU / DDU | Contact rubber seal, one or both sides |
| C2 / C3 / C4 / C5 | Radial internal clearance smaller (C2) or greater (C3–C5) than normal |
| CM | Clearance range for electric motor applications |
| P6 / P5 / P4 / P2 | Accuracy to ISO tolerance class 6, 5, 4 or 2 |
| M / MA / MB | Machined brass cage, outer-ring (MA) or inner-ring (MB) guided |
| T / TN | Polyamide (resin) cage |
| K / K30 | Tapered bore, taper 1:12 or 1:30 |
| DB / DF / DT | Matched pair: back-to-back, face-to-face or tandem |
| W33 | Annular groove and three lubrication holes in the outer ring |