NK 40/20 TN bearing
40 × 50 mm · dynamic rating 29.7 kN · static rating 60 kN. Dimensions, load ratings, designation meaning, life estimates and equivalent parts.
NK 40/20 TN specification
| Designation | NK 40/20 TN |
| Type | Needle roller bearing |
| Series | — |
| Bore diameter d | 40 mm |
| Outside diameter D | 50 mm |
| Basic dynamic load rating C | 29.7 kN (29,700 N) |
| Basic static load rating C0 | 60 kN (60,000 N) |
| Ratio C0/C | 2.02 |
| Speed guide, grease lubrication | 11,000 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 NK 40/20 TN means
| Code | Meaning |
|---|---|
| NK | Needle roller bearing, machined ring with flange, no inner ring — the hardened/ground shaft itself serves as the inner raceway |
| 40 | Bore (Fw) = 40 mm — stated directly, not a bore code |
| 20 | Bearing width = 20 mm — stated directly |
| TN | Glass-fibre-reinforced PA66 cage |
Basic rating life of the NK 40/20 TN
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 NK 40/20 TN with C = 29.7 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 5.94 kN on this bearing. Use the Load Calculator to work out P for your actual radial and axial loads.
Equivalents of the NK 40/20 TN
Brand-by-brand equivalents for this exact designation are not yet in the Rotec AI cross-reference tables. The Cross-Reference tool accepts SKF, FAG, NSK, NTN, Timken, Koyo and NRB designations, and shows what is catalogued.
Where the NK 40/20 TN is used
Needle roller bearings are chosen for: High radial load in limited radial space. Typical equipment: Transmissions, actuators, mobile equipment, compact machinery. Requires hardened raceways or inner ring; alignment sensitivity.
Other sizes in the same series
The NK 40/20 TN is size 7 of 24 in the Rotec AI catalogue for the “” series. The next size down, the NK 35/20 TN, has a bore of 35 mm and a dynamic rating of 27.5 kN. The next size up, the NK 45/20 TN, has a bore of 45 mm and a rating of 31.4 kN (+6%).
Common problems on bearings like the NK 40/20 TN
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 NK 40/20 TN
What are the dimensions of a NK 40/20 TN bearing?
The NK 40/20 TN has a bore of 40 mm and an outside diameter of 50 mm. It is a needle roller bearing.
What is the load rating of a NK 40/20 TN bearing?
In the Rotec AI catalogue the NK 40/20 TN has a basic dynamic load rating C of 29.7 kN and a basic static load rating C0 of 60 kN. Always confirm against the manufacturer's current catalogue.
What is the equivalent of a NK 40/20 TN bearing?
Brand equivalents for the NK 40/20 TN are not yet in the Rotec AI tables. Use the Cross-Reference tool to check other designations.