The 6903 (17x30x7mm) appears in mountain bike rear hubs, endurance road hubs, and some freehub designs. Our ceramic version upgrades these with Grade 3 silicon nitride balls, DLC-coated races, and ABEC-7 tolerances. Sold individually.
What You Get
- ✓ Grade 3 Si₃N₄ ceramic balls — harder and smoother than steel
- ✓ DLC-coated races reduce surface friction and extend life
- ✓ ABEC-7 precision tolerances for exact bearing bore fit
- ✓ 2RS contact seals: trail-capable protection
- ✓ Sold individually — order the quantity you need
Technical Specifications
| Sold As |
Individual bearing |
| Seal Type |
2RS contact seals |
| Tolerance |
ABEC-7 |
| Dimensions |
17x30x7mm |
| Expected Life |
8,000–15,000 miles |
| Race Material |
52100 Chromium Steel, DLC Coated |
| Bearing Material |
Grade 3 Silicon Nitride (Si₃N₄) |
Compatibility
MTB rear hubs (selected models)
Endurance road rear hubs
Industry Nine MTB hub bearings
White Industries MTB hubs
Any application requiring a 17x30x7mm bearing