NKI22-20 bearing: complete specifications & equivalents
The NKI22-20 is a DIN 616 radial bearing sized 22 x 34 x 20 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | SKF |
| Bore diameter d | 22 mm |
| Outer diameter D | 34 mm |
| Width B | 20 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | none |
| Basic dynamic load rating C | 19.4 kN |
| Basic static load rating C0 | 34.5 kN |
| Fatigue load limit Pu | 4.25 kN |
| Reference speed (thermal) | 15000 rpm |
| Limiting speed (mechanical) | 17000 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 65 g |
| Manufacturer designation | NKI 22/20 |
| 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 & NKI-series range
| Bore d | 0.866 in |
|---|---|
| Outer diameter D | 1.339 in |
| Width B | 0.787 in |
| ISO bore code | — |
| Radial section height (D−d)/2 | 6 mm |
| Smallest bore in NKI-series | 5 mm |
| Largest outer diameter in NKI-series | 130 mm |
| Width range across NKI-series | 12–40 mm |
| Bore position in NKI-series (smallest first) | 10 of 30 |
| Bore above smallest NKI-series size | 17 mm |
Cross references & equivalents
No verified interchange data yet. Send an inquiry and our team will confirm equivalents manually.
How the NKI22-20 model number is decoded
NKI 22/20 is a machined-ring needle roller bearing with an inner ring: flanged outer ring plus a separate 22 mm bore inner ring, so the shaft seat needs only ordinary tolerance, as tabulated by SKF in SKF catalogue PUB BU/P1 17000. In SKF nomenclature the leading letters mark a machined-ring needle bearing with inner ring: figures state 22 mm d and 20 mm B, the 34 mm outside diameter from the machined-ring needle roller bearings with inner ring, and the 2RS suffix would add contact seals. Inner rings are separable: order replacement inner rings separately by d×D×B, since the outer ring and roller assembly survive journals that ruin an inner raceway. Speed planning separates the two ceilings: 15,000 r/min thermal reference and 17,000 r/min mechanical limiting — needle bearings tolerate high rpm only with adequate lubricant film at the 22 mm seat. Mounting: heat or press the inner ring onto the 22 mm k5 seat (max 120 °C), fit the flanged outer ring into the H7 housing bore, and check the 20 mm assembly for free rotation before applying load.
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
- needle edge loading and raceway denting when the shaft deflects beyond the compensation range
- cage pocket wear and roller skew after sustained operation with too little radial preload
- grease starvation at the roller ends when relubrication intervals are stretched in dirty duty
- rolling-contact fatigue spalling after the rated L10 life
- inner-ring bore fretting on a loose shaft seat, migrating hard particles into the rolling contact
Selection pitfalls — read before you substitute
- On a 22 mm seat the housing bore quality dominates life: a bore 0.02 mm out of round pinches the 34 mm ring or cup into a lobed shape, and the rollers then trace the housing's geometry error, not the design load.
- Reference and limiting speeds are different limits: the 15,000 r/min reference is the thermal criterion under load, The limiting value is mechanical; the reference value is thermal under load, and grease choice moves it substantially.
- Hardness is load capacity: in families without an inner ring the 22 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 19.4/34.5 kN ratings and 65 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
Is the NKI 22/20 sealed?
No — the open execution relies on housing seals; 2RS executions of the 49 series add contact seals with a wider outer ring as a separate order number.
Which dimensions does the NKI 22/20 have?
A NKI 22/20 measures 22 mm bore/Fw × 34 mm outside diameter × 20 mm width (0.866 × 1.339 × 0.787 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 19.4 kN, static C0 34.5 kN, fatigue limit Pu 4.25 kN, limiting speed 17,000 r/min, reference speed 15,000 r/min, mass about 65 g.
What does NKI 22/20 mean in SKF part numbering?
The letters mark a machined-ring needle roller bearing with inner ring: 22 mm bore, 20 mm width, 34 mm OD per the series plan. The hardened inner ring is the raceway, so an ordinary k5 shaft seat suffices.
Does the NKI 22/20 need a hardened and ground shaft?
Yes — that is the point of this family. The NKI 22/20 carries its own hardened, ground inner ring on a 22 mm seat, so the shaft needs only a normal k5/j6 finish. The inner ring is separable and replaceable.
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.