Knowledge · Reference
Bearing suffix glossary
What 2RS, C3, TN9 or W33 stand for: all common suffixes and prefixes of SKF, FAG/INA, NSK, NTN and Koyo — sorted by function, with manufacturer mapping.
Seals & shields
| Code | Manufacturer | Meaning |
|---|---|---|
| 2RS1 / RS1 | SKF | Contact seal (NBR), both sides / one side |
| 2RSH / RSH | SKF | Contact seal, reinforced design (smaller sizes) |
| 2RSR / RSR | FAG | Contact seal, both sides / one side |
| DDU / DU | NSK | Contact seal, both sides / one side |
| LLU / LU | NTN | Contact seal, both sides / one side |
| 2RU / RU | Koyo | Contact seal, both sides / one side |
| 2RZ / RZ | SKF | Non-contact seal (NBR) with a narrow gap to the inner ring |
| 2RSL / RSL | SKF | Low-friction seal (NBR), virtually no contact; seals better than non-contact RZ, less friction than contact RSH |
| VV / V | NSK | Non-contact seal, both sides / one side |
| LLB | NTN | Non-contact seal, both sides |
| 2Z / Z | SKF, FAG et al. | Steel shields, both sides / one side (non-contact) |
| ZZ | NSK, NTN, Koyo, ZEN | Shields both sides — equivalent to 2Z |
Internal clearance
| Code | Manufacturer | Meaning |
|---|---|---|
| C2 | all | Clearance smaller than normal |
| CN (no suffix) | all | Normal clearance — usually not marked |
| C3 | all | Clearance greater than normal — most common (motors, thermal expansion) |
| C4 | all | Clearance greater than C3 |
| C5 | all | Clearance greater than C4 — extreme cases |
Cage
| Code | Manufacturer | Meaning |
|---|---|---|
| TN9 | SKF | Glass-fibre reinforced PA66 cage |
| TVP / TVH / TVEB | FAG | Glass-fibre reinforced polyamide cage |
| M / MA / MB | SKF, FAG | Machined brass cage; MA outer-ring, MB inner-ring guided |
| F / FA / FB | SKF, FAG | Machined steel cage |
| J / Y | SKF | Pressed steel (J) or brass (Y) sheet cage |
| E / E1 | SKF / FAG | Reinforced design: larger rolling element set, higher ratings |
| CA / CC | SKF (SRB) | SRB design: brass cage (CA) or steel cage, roller-guided (CC) |
| V | FAG, ZEN et al. | Full complement — no cage, maximum capacity, reduced speed |
Precision (tolerance classes)
| Code | Manufacturer | Meaning |
|---|---|---|
| P0 (no suffix) | all | Normal tolerance (ISO 492) — ABEC 1 |
| P6 | all | Increased precision — ABEC 3 |
| P5 | all | High precision — ABEC 5 |
| P4 / P4S | all / FAG | Very high precision (spindle bearings) — ABEC 7 |
| SP / UP | FAG | Special / ultra precision for machine-tool spindles |
Bore, grooves & mounting
| Code | Manufacturer | Meaning |
|---|---|---|
| K | all | Tapered bore 1:12 (adapter sleeve mounting) |
| K30 | all | Tapered bore 1:30 (SRB series 240/241) |
| N | all | Snap-ring groove in outer ring |
| NR | all | Snap-ring groove with snap ring fitted |
| W33 | all (SRB) | Lubrication groove and three holes in outer ring (SRB) |
Heat stabilisation & lubricant
| Code | Manufacturer | Meaning |
|---|---|---|
| S0 / S1 / S2 / S3 | all | Dimensionally stabilised to 150 / 200 / 250 / 300 °C |
| VA208 | SKF | High-temperature bearing, not heat stabilisation: segmented graphite cage, manganese-phosphate-coated rings, clearance of multiples of C5, up to 350 °C |
| HT | SKF et al. | High-temperature grease fill |
| LT | SKF et al. | Low-temperature grease fill |
| WT | SKF | Wide-temperature-range grease |
| C3VL0241 | SKF | C3 clearance + INSOCOAT outer-ring coating (current-insulating) |
| J20AA / J20AB | FAG | Current-insulating ceramic coating, outer / inner ring |
Matching & arrangement (ACBB)
| Code | Manufacturer | Meaning |
|---|---|---|
| DB | all | Paired back-to-back (O) — high moment rigidity |
| DF | all | Paired face-to-face (X) |
| DT | all | Paired in tandem — high axial load one direction |
| B / A / AC | SKF (B also FAG) | Contact angle of single row ACBB: B = 40°, A = 30°, AC = 25°; SKF E means optimized internal design, not a contact angle |
| ATN9 / DNRCBM | SKF | Double row ACBB: A = no filling slots, TN9 = polyamide cage; D = two-piece inner ring, NR = snap ring groove with snap ring, CB = controlled axial clearance, M = machined brass cage |
Prefixes
| Code | Manufacturer | Meaning |
|---|---|---|
| S… | FAG, ZEN | Stainless steel bearing (e.g. S6205) |
| W… | SKF | Stainless deep groove bearing (e.g. W6205) |
| SS… | ZEN et al. | Stainless execution (miniature and inch series) |
| R… / RLS… | all / SKF | Inch-dimension deep groove bearings |
| MR… | all | Miniature bearing (metric) |
| NU / NJ / NUP / N | all (CRB) | Cylindrical roller design: rib layout defines axial guidance |
| GE… / SA… / SI… | all | Spherical plain bearings / rod ends |
Suffixes are manufacturer-specific and can differ per series — the manufacturer’s catalogue is always authoritative. If a code is missing or you are unsure which execution you need, our application engineers can help.