NU 309 ECP bearing
45 × 100 mm · dynamic rating 112 kN · static rating 100 kN. Dimensions, load ratings, designation meaning, life estimates and equivalent parts.
NU 309 ECP specification
| Designation | NU 309 ECP |
| Type | Cylindrical roller bearing |
| Series | NU3 medium |
| Bore diameter d | 45 mm |
| Outside diameter D | 100 mm |
| Basic dynamic load rating C | 112 kN (112,000 N) |
| Basic static load rating C0 | 100 kN (100,000 N) |
| Ratio C0/C | 0.89 |
| Speed guide, grease lubrication | 8,500 rpm |
| Life exponent p | 10/3 (roller 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 NU 309 ECP means
| Code | Meaning |
|---|---|
| NU | No flange on the inner ring, two flanges on the outer ring — inner ring can float axially |
| 309 | medium dimension series — bore code "09" = 9 × 5 = 45 mm |
| EC | Optimized internal design with more and/or larger rollers |
| P | Glass-fibre-reinforced PA66 cage, roller-centred |
Basic rating life of the NU 309 ECP
Basic rating life is L10 = (C / P)p million revolutions, where P is the equivalent dynamic load and p = 10/3 (roller bearing). For a NU 309 ECP with C = 112 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% | 39 | 430 | 220 |
| 5 | 20.0% | 214 | 2,400 | 1,200 |
| 8 | 12.5% | 1,024 | 11,400 | 5,700 |
| 12 | 8.3% | 3,956 | 44,000 | 22,000 |
For example, a C / P of 5 means the equivalent load is 22.4 kN on this bearing. Use the Load Calculator to work out P for your actual radial and axial loads.
Equivalents of the NU 309 ECP
Brand-by-brand equivalents for this exact designation are not shown here. The Cross-Reference tool accepts SKF, FAG, NSK, NTN, Timken, Koyo and NRB designations, and shows what is catalogued.
Where the NU 309 ECP is used
Cylindrical roller bearings are chosen for: High radial load and high speed; separable arrangements. Typical equipment: Gearboxes, traction motors, rolling mills, generators. Some variants carry axial load; common in railway drive systems.
Other sizes in the same series
The NU 309 ECP belongs to the “NU3 medium” series. The next size down, the NU 308 ECP, has a bore of 40 mm and a dynamic rating of 93 kN. The next size up, the NU 310 ECP, has a bore of 50 mm and a rating of 127 kN (+13%).
Common problems on bearings like the NU 309 ECP
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 NU 309 ECP
What are the dimensions of a NU 309 ECP bearing?
The NU 309 ECP has a bore of 45 mm and an outside diameter of 100 mm. It is a cylindrical roller bearing. Series: NU3 medium.
What is the load rating of a NU 309 ECP bearing?
In the Rotec AI catalogue the NU 309 ECP has a basic dynamic load rating C of 112 kN and a basic static load rating C0 of 100 kN. Always confirm against the manufacturer's current catalogue.
What is the equivalent of a NU 309 ECP bearing?
Use the Cross-Reference tool in Rotec AI to check brand equivalents for the NU 309 ECP.