6903 Bearing
Bore (d) 17 mm
Outside diameter (D) 30 mm
Width (B) 7 mm
Inches (bore × OD × width) 0.6693 × 1.1811 × 0.2756″
Deep-groove ball bearing, thin section (6900) series. Seal/shield suffixes (ZZ, 2RS, …) change the closures, never these dimensions — a 6903-ZZ and 6903-2RS are the same size.
What the number means
- 6 — deep-groove ball bearing
- 9 — dimension series (thin section (6900))
- 03 — bore code (03 → 17 mm)
Neighboring sizes (thin section (6900) series)
| Designation | Bore | OD | Width |
|---|---|---|---|
| 6901 | 12 mm | 24 mm | 6 mm |
| 6902 | 15 mm | 28 mm | 7 mm |
| 6903 | 17 mm | 30 mm | 7 mm |
| 6904 | 20 mm | 37 mm | 9 mm |
| 6905 | 25 mm | 42 mm | 9 mm |
Same bore, other series
Fits the same 17 mm shaft with a different OD/width envelope and load capacity.
- 6803 — 17 × 26 × 5 mm (thin section (6800))
- 6003 — 17 × 35 × 10 mm (extra light (6000))
- 6203 — 17 × 40 × 12 mm (light (6200))
- 6303 — 17 × 47 × 14 mm (medium (6300))
Common suffixes on a 6903
| 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) |