6318 bearing
90 × 190 mm · dynamic rating 151 kN · static rating 108 kN. Dimensions, load ratings, designation meaning, life estimates and equivalent parts.
6318 specification
| Designation | 6318 |
| Type | Deep groove ball bearing |
| Series | 63 medium |
| Bore diameter d | 90 mm |
| Outside diameter D | 190 mm |
| Basic dynamic load rating C | 151 kN (151,000 N) |
| Basic static load rating C0 | 108 kN (108,000 N) |
| Ratio C0/C | 0.72 |
| Speed guide, grease lubrication | 4,800 rpm |
| Life exponent p | 3 (ball bearing) |
Values come from the Rotec AI bearing catalogue and are indicative. Confirm against the manufacturer's current catalogue before ordering. Not every dimension (such as width) is listed here.
What the designation 6318 means
| Code | Meaning |
|---|---|
| 63 | Deep groove ball bearing, medium dimension series |
| 18 | bore code "18" = 18 × 5 = 90 mm |
Basic rating life of the 6318
Basic rating life is L10 = (C / P)p million revolutions, where P is the equivalent dynamic load and p = 3 (ball bearing). For a 6318 with C = 151 kN, the table shows what that gives at different load levels. It is the ISO 281 basic life only: it does not include lubrication, contamination, misalignment or reliability modifiers.
| C / P | P as share of C | L10 (million rev) | L10 at 1,500 rpm | L10 at 3,000 rpm |
|---|---|---|---|---|
| 3 | 33.3% | 27 | 300 | 150 |
| 5 | 20.0% | 125 | 1,400 | 690 |
| 8 | 12.5% | 512 | 5,700 | 2,800 |
| 12 | 8.3% | 1,728 | 19,200 | 9,600 |
For example, a C / P of 5 means the equivalent load is 30.2 kN on this bearing. Use the Load Calculator to work out P for your actual radial and axial loads.
Equivalents of the 6318 from other brands
Deep groove ball bearings follow the ISO basic designation system, so the base number 6318 means the same bore (90 mm) and outside diameter (190 mm) at the major makers. Only the suffixes differ. For sealed versions, common suffixes are -2RS1 or -2Z at SKF, -2RSR or -2ZR at FAG, DDU or ZZ at NSK, and LLU or ZZ at NTN. Check clearance class, grease and seal type before substituting. For brand-specific part numbers, use the Cross-Reference tool.
Where the 6318 is used
Deep-groove ball bearings are chosen for: Radial load with moderate axial load; high-speed compact equipment. Typical equipment: Motors, fans, pumps, gearboxes, auxiliaries. Single/multi-row; insulated or stainless variants available.
Other sizes in the same series
The 6318 belongs to the “63 medium” series. The next size down, the 6317, has a bore of 85 mm and a dynamic rating of 140 kN. The next size up, the 6319, has a bore of 95 mm and a rating of 159 kN (+5%).
Common problems on bearings like the 6318
Most field failures trace back to lubrication, contamination, fits and alignment rather than the bearing itself. These guides explain how to recognise and prevent them:
Questions about the 6318
What are the dimensions of a 6318 bearing?
The 6318 has a bore of 90 mm and an outside diameter of 190 mm. It is a deep groove ball bearing. Series: 63 medium.
What is the load rating of a 6318 bearing?
In the Rotec AI catalogue the 6318 has a basic dynamic load rating C of 151 kN and a basic static load rating C0 of 108 kN. Always confirm against the manufacturer's current catalogue.
What is the equivalent of a 6318 bearing?
Use the Cross-Reference tool in Rotec AI to check brand equivalents for the 6318.