NKIS25 bearing: complete specifications & equivalents
The NKIS25 is a DIN 616 radial bearing sized 25 x 47 x 22 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | SKF |
| Bore diameter d | 25 mm |
| Outer diameter D | 47 mm |
| Width B | 22 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | none |
| Basic dynamic load rating C | 34.1 kN |
| Basic static load rating C0 | 46.5 kN |
| Fatigue load limit Pu | 5.7 kN |
| Reference speed (thermal) | 12000 rpm |
| Limiting speed (mechanical) | 13000 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 160 g |
| Manufacturer designation | NKIS 25 |
| Standard | DIN 616 |
| Catalog version | SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.4 machined rings with flanges, with an inner ring |
| Last verified | 2026-09-26 |
Source: catalog reference (SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.4 machined rings with flanges, with an inner ring) · extracted 2026-09-26
Parameters extracted from the official SKF Rolling Bearings catalogue (SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.4 machined rings with flanges, with an inner ring); 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 & NKIS-series range
| Bore d | 0.984 in |
|---|---|
| Outer diameter D | 1.85 in |
| Width B | 0.866 in |
| ISO bore code | — |
| Radial section height (D−d)/2 | 11 mm |
| Smallest bore in NKIS-series | 15 mm |
| Largest outer diameter in NKIS-series | 95 mm |
| Width range across NKIS-series | 20–28 mm |
| Bore position in NKIS-series (smallest first) | 4 of 12 |
| Bore above smallest NKIS-series size | 10 mm |
Cross references & equivalents
No verified interchange data yet. Send an inquiry and our team will confirm equivalents manually.
How the NKIS25 model number is decoded
NKIS 25 is a machined-ring needle roller bearing with an inner ring: flanged outer ring plus a separate 25 mm bore inner ring, so the shaft seat needs only ordinary tolerance, as tabulated by SKF in SKF catalogue PUB BU/P1 17000. The designation NKIS 25 tells you the envelope — 25×47×22 mm — and the family tells you the construction: complete bearing, replaceable inner ring, flanged outer ring retaining the needle rollers. TN polymer cage executions run quieter and tolerate grease-lubricated pivot duty; steel cage executions remain the choice for higher temperature or oil-bath lubrication. Speed planning separates the two ceilings: 12,000 r/min thermal reference and 13,000 r/min mechanical limiting — needle bearings tolerate high rpm only with adequate lubricant film at the 25 mm seat. For NA 49 2RS executions the wider outer ring changes the housing depth: verify the 22 mm width and s offset dimensions against the open execution before reusing an existing bore.
Typical equipment & failure modes
Common applications
- wheel and lever pivots needing a replaceable inner ring
- conveyor roller ends and return rollers
- agricultural implement pivots and cutter heads
- electric motor armature shafts with ground seats
Known failure patterns
- raceway spalling once the catalogue L10 life is exceeded or after overload events
- polymer cage deformation when the local temperature exceeds the 120 °C sustained limit
- abrasive paste formation from dust ingressing past open ends without effective housing seals
- hard-particle indentation in unfiltered lubricant
- inner-ring bore fretting on a loose shaft seat, migrating hard particles into the rolling contact
Selection pitfalls — read before you substitute
- On a 25 mm seat the housing bore quality dominates life: a bore 0.02 mm out of round pinches the 47 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 25 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 34.1/46.5 kN ratings are SKF catalogue values for this exact execution (NKIS 25); ratings can be revised without the order number changing, so keep the catalogue version (SKF catalogue PUB BU/P1 17000) with the drawing.
- The 34.1/46.5 kN ratings and 160 g mass are SKF catalogue values transcribed from ch. 7.4 of PUB BU/P1 17000 (PDF table page 640); combined-type axial ratings appear in the text above because the structured record carries radial values only.
Frequently asked questions
What are the dimensions and ratings of the NKIS 25?
A NKIS 25 measures 25 mm bore/Fw × 47 mm outside diameter × 22 mm width (0.984 × 1.85 × 0.866 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 34.1 kN, static C0 46.5 kN, fatigue limit Pu 5.7 kN, limiting speed 13,000 r/min, reference speed 12,000 r/min, mass about 160 g.
How is the NKIS 25 designation read?
The letters mark a machined-ring needle roller bearing with inner ring: 25 mm bore, 22 mm width, 47 mm OD per the series plan. The hardened inner ring is the raceway, so an ordinary k5 shaft seat suffices.
Can the NKIS 25 run on an unhardened shaft?
Yes — that is the point of this family. The NKIS 25 carries its own hardened, ground inner ring on a 25 mm seat, so the shaft needs only a normal k5/j6 finish. The inner ring is separable and replaceable.
How should the NKIS 25 be mounted?
Mount the inner ring on the 25 mm seat first (induction heat, max 120 °C, or press), then fit the flanged outer ring into the H7 housing bore. Verify free rotation and, for 2RS executions, check the wider outer ring against the housing depth.
Reviewed & verified by the MPN Base engineering desk against source catalog SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.4 machined rings with flanges, with an inner ring on 2026-09-26. Read our editorial & correction policy.