NKIA5901 bearing: complete specifications & equivalents
The NKIA5901 is a DIN 616 radial bearing sized 12 x 24 x 16 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | SKF |
| Bore diameter d | 12 mm |
| Outer diameter D | 24 mm |
| Width B | 16 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | none |
| Basic dynamic load rating C | 8.09 kN |
| Basic static load rating C0 | 9.65 kN |
| Fatigue load limit Pu | 1.14 kN |
| Reference speed (thermal) | 22000 rpm |
| Limiting speed (mechanical) | 26000 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 40 g |
| Manufacturer designation | NKIA 5901 |
| Standard | DIN 616 |
| Catalog version | SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.7 needle roller / angular contact ball bearings |
| Last verified | 2026-09-26 |
Source: catalog reference (SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.7 needle roller / angular contact ball bearings) · extracted 2026-09-26
Parameters extracted from the official SKF Rolling Bearings catalogue (SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.7 needle roller / angular contact ball bearings); SKF® and SKF Explorer® are trademarks of AB SKF, used here for identification only — mpnbase is not an authorized SKF distributor. Boundary dimensions are ISO 15 interchangeable; current production values may differ, verify at skf.com.
Dimensions in inches & NKIA-series range
| Bore d | 0.472 in |
|---|---|
| Outer diameter D | 0.945 in |
| Width B | 0.63 in |
| ISO bore code | 01 |
| Radial section height (D−d)/2 | 6 mm |
| Smallest bore in NKIA-series | 12 mm |
| Largest outer diameter in NKIA-series | 100 mm |
| Width range across NKIA-series | 16–40 mm |
| Bore position in NKIA-series (smallest first) | 1 of 15 |
| Bore above smallest NKIA-series size | 0 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| NKI12-16 | SKF | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 12×24×16 mm envelope, but catalogue C/C0 differ between the executions (8.09/9.65 vs 11.7/15.3 kN) — boundary dimensions match, not a load-rating equivalent. |
Interchange levels: full standard interchange · partial verify parameters · verify manual confirmation required. Links resolve to the equivalent model's specification page where available.
How the NKIA5901 model number is decoded
NKIA 5901 is the combined needle roller / angular contact ball bearings entry for a 12 mm shaft: needle rollers run the radial load while the angular contact ball set takes axial force primarily in one direction, in a single machined envelope of 12×24×16 mm. The NKIA 5901 code breaks into series letters (needle roller + ball), dimension series 59, and the two-digit bore reference for 12 mm; the 16 mm width covers both the roller cage and the offset ball set (offset per catalogue s column). The combined unit is greased for life at assembly in many applications; relubrication, where provided, must reach both the roller cage and the ball set through the same axial bore features. Speed ceilings differ by part: 22,000 r/min thermal reference and 26,000 r/min limiting — the thrust element governs, since its washer faces see sliding components of contact. Fit the combined unit so the ball raceway offset faces the working axial load, check rotation in both directions, and preload if required with the washer stack the catalogue recommends.
Typical equipment & failure modes
Common applications
- spindle heads needing compact radial-plus-axial support
- lead-screw and ball-screw support positions
- pump rotors with hydraulic axial pull
- bevel gear shafts with moderate axial force
Known failure patterns
- raceway spalling once the catalogue L10 life is exceeded or after overload events
- cage pocket wear and roller skew after sustained operation with too little radial preload
- abrasive paste formation from dust ingressing past open ends without effective housing seals
- false brinelling of standby equipment under external vibration
- thrust washer raceway wear from reverse axial shocks the one-direction thrust part cannot carry
Selection pitfalls — read before you substitute
- On a 12 mm seat the housing bore quality dominates life: a bore 0.02 mm out of round pinches the 24 mm ring or cup into a lobed shape, and the rollers then trace the housing's geometry error, not the design load.
- Hardness is load capacity: in families without an inner ring the 12 mm journal must hold 58–64 HRC with a ground finish; a surface that looks fine but sits at 45 HRC will rib the raceway within weeks.
- The quoted 8.09/9.65 kN ratings are SKF catalogue values for this exact execution (NKIA 5901); ratings can be revised without the order number changing, so keep the catalogue version (SKF catalogue PUB BU/P1 17000) with the drawing.
- Minimum axial load is a real requirement: below the catalogue minimum the thrust elements skid, polish their raceways and lose them — springs or preload washers belong in the arrangement drawing, not the troubleshooting notes.
- Height stack-up is easy to mis-check: the ball-raceway part adds height beyond a plain needle bearing, and clamping the stack solid over it preloads the thrust set beyond its rating.
- The 8.09/9.65 kN ratings and 40 g mass are SKF catalogue values transcribed from ch. 7.7 of PUB BU/P1 17000 (PDF table page 654); combined-type axial ratings appear in the text above because the structured record carries radial values only.
Frequently asked questions
What limits the service life of a NKIA 5901?
Beyond the L10 rating, the practical limits are journal/raceway hardness for the 12 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 6.0 mm radial section leaves no reserve once a raceway is dented or ribboned.
What are the dimensions and ratings of the NKIA 5901?
A NKIA 5901 measures 12 mm bore/Fw × 24 mm outside diameter × 16 mm width (0.472 × 0.945 × 0.63 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 8.09 kN, static C0 9.65 kN, fatigue limit Pu 1.14 kN, limiting speed 26,000 r/min, reference speed 22,000 r/min, mass about 40 g. Axial ratings of the ball part: dynamic Ca 2.07 kN (Ca), static C0a 1.92 kN (C0a); angular contact geometry leans axial capacity toward one direction.
How is the NKIA 5901 designation read?
NKIA combines a needle roller cage with an angular contact ball bearing in one unit; 595901 gives the series and 12 mm bore. The offset (a catalogue-listed offset) positions the ball raceway inside the 16 mm overall width.
Can the NKIA 5901 run on an unhardened shaft?
The needle roller part of the NKIA 5901 rides directly on the 12 mm journal, so it must be hardened to 58–64 HRC and ground; the ball set runs on its own integrated raceways. There is no inner-ring variant — harden the shaft or move to a separate bearing arrangement.
Reviewed & verified by the MPN Base engineering desk against source catalog SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.7 needle roller / angular contact ball bearings on 2026-09-26. Read our editorial & correction policy.