6308 Bearing
Bore (d) 40 mm
Outside diameter (D) 90 mm
Width (B) 23 mm
Inches (bore × OD × width) 1.5748 × 3.5433 × 0.9055″
Deep-groove ball bearing, medium (6300) series. Seal/shield suffixes (ZZ, 2RS, …) change the closures, never these dimensions — a 6308-ZZ and 6308-2RS are the same size.
What the number means
- 6 — deep-groove ball bearing
- 3 — dimension series (medium (6300))
- 08 — bore code × 5 = 40 mm
Neighboring sizes (medium (6300) series)
| Designation | Bore | OD | Width |
|---|---|---|---|
| 6306 | 30 mm | 72 mm | 19 mm |
| 6307 | 35 mm | 80 mm | 21 mm |
| 6308 | 40 mm | 90 mm | 23 mm |
| 6309 | 45 mm | 100 mm | 25 mm |
| 6310 | 50 mm | 110 mm | 27 mm |
Same bore, other series
Fits the same 40 mm shaft with a different OD/width envelope and load capacity.
- 6808 — 40 × 52 × 7 mm (thin section (6800))
- 6908 — 40 × 62 × 12 mm (thin section (6900))
- 6008 — 40 × 68 × 15 mm (extra light (6000))
- 6208 — 40 × 80 × 18 mm (light (6200))
Common suffixes on a 6308
| Suffix | Meaning |
|---|---|
| ZZ / 2Z | steel shields both sides (metal, non-contact) |
| Z | steel shield, one side |
| 2RS | contact rubber seals both sides (SKF 2RS1, NSK DDU, NTN LLU) |
| RS | contact rubber seal, one side |
| 2RZ | low-friction non-contact seals both sides (NSK VV, NTN LLB) |
| C3 | radial internal clearance greater than Normal (common in motors) |
| C2 | radial internal clearance smaller than Normal |
| NR | snap ring groove in the outer ring, with snap ring |
| P6 / P5 / P4 | ISO precision classes (≈ ABEC 3 / 5 / 7) |