NKS22-XL bearing: complete specifications & equivalents
The NKS22-XL is a ISO 15 radial bearing sized 22 x 35 x 20 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | FAG |
| Bore diameter d | 22 mm |
| Outer diameter D | 35 mm |
| Width B | 20 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | steel |
| Basic dynamic load rating C | 27.5 kN |
| Basic static load rating C0 | 28 kN |
| Fatigue load limit Pu | 5 kN |
| Reference speed (thermal) | 10900 rpm |
| Limiting speed (mechanical) | 18500 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 61.5 g |
| Manufacturer designation | NKS22-XL |
| Standard | ISO 15 |
| Catalog version | HR1 2026-09-25 |
| Last verified | 2026-09-30 |
Source: catalog reference (HR1 2026-09-25) · extracted 2026-09-30
Parameters extracted from the official FAG Rolling Bearings catalogue (HR1 2026-09-25); FAG® is a trademark of Schaeffler Technologies AG & Co. KG, used here for identification only — mpnbase is not an authorized FAG/Schaeffler distributor. Boundary dimensions are ISO 15 interchangeable; current production values may differ, verify at schaeffler.com.
Dimensions in inches & nks-series range
| Bore d | 0.866 in |
|---|---|
| Outer diameter D | 1.378 in |
| Width B | 0.787 in |
| ISO bore code | — |
| Radial section height (D−d)/2 | 6.5 mm |
| Smallest bore in nks-series | 20 mm |
| Largest outer diameter in nks-series | 95 mm |
| Width range across nks-series | 20–28 mm |
| Bore position in nks-series (smallest first) | 2 of 18 |
| Bore above smallest nks-series size | 2 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| NKS22 | ISO 15 | full Dimensions and internal design equivalent — standard interchange. | ISO 15 boundary-dimension envelope; brand-specific OEM equivalents (NSK/FAG/NTN) pending multi-source data. |
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 NKS22-XL model number is decoded
envelope 22×35×20 mm: 22 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 6.5 mm radial section packed with small-diameter needle rollers C is 27.5 kN and C0 28 kN at the 22 mm seat; the C/C0 ratio of 0.98 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 35 mm outside diameter the fatigue load limit Cur is 5 kN, the limiting speed 18,500 r/min and the thermal reference speed 10,900 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.25 kN/mm and per millimetre of width 1.38 kN/mm — the reason 20 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 61.5 g, just 0.09 g per mm² of projected 35×20 mm envelope, which keeps unbalanced forces low in fast-actuating linkages at 22 mm bore this size balances the 35 mm outside diameter against machineability of the adjacent parts — the most frequently specified band in the HR1 range The thin 6.5 mm section makes the 61.5 g bearing sensitive to seat geometry — a tapered or lobed journal preloads part of the needle set and shows up as local pitting With Cur 5 kN and a 18,500 r/min limiting speed the unit suits pivots, rocker arms, pumps and compact gear trains running on hardened pins The -XL suffix is the Schaeffler X-life mark: interchangeable envelope with the basic bearing, but higher load capacity and lower running temperature at the 18,500 r/min limit. Typical applications include hydraulic and pneumatic pump eccentrics, copying and printing machine mechanisms and agricultural machine pivots and linkages, where the 35 mm outside diameter and 27.5 kN dynamic rating match the duty. In hydraulic and pneumatic pump eccentrics the unit fits a compact 22 mm seat, and in copying and printing machine mechanisms the 61.5 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for agricultural machine pivots and linkages, relying on the 20 mm width and the published 28 kN static rating. On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions. Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting.
Typical equipment & failure modes
Common applications
- two-stroke and compressor piston pins
- agricultural machine pivots and linkages
- rocker arms and valve trains
- small electric motor accessory drives
Known failure patterns
- journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough
- needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack
- raceway pitting from contamination drawn through the open ends of an unsealed bearing
- edge loading at the roller ends from a tapered or lobed shaft seat
- cage damage from shock loading or from pressing the bearing through the wrong ring
- lubricant starvation on fast reciprocating strokes that never fully rotate the needles
- false brinelling during stationary transport vibration
- spalling from excessive interference that removes the radial clearance
- roller wear from misaligned connecting-rod eyes and rocker bores
Selection pitfalls — read before you substitute
- On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions.
- Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting.
- Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone.
Frequently asked questions
What are the dimensions of the NKS22-XL?
The NKS22-XL is a NKS heavy-section machined-ring needle roller bearing without inner ring with 35 mm outside diameter, 22 mm bore and 20 mm width, envelope 22×35×20 mm. Mass is 61.5 g.
What does the NKS22-XL designation mean in the FAG/INA HR1 catalogue?
NKS22-XL identifies this NKS heavy-section machined-ring needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 22×35×20 mm and the catalogue ratings are C 27.5 kN, C0 28 kN, Cur 5 kN.
What is the load capacity of the NKS22-XL?
The basic dynamic load rating C is 27.5 kN and the basic static load rating C0 is 28 kN; the fatigue load limit Cur is 5 kN.
What is the maximum speed of the NKS22-XL?
The limiting speed is 18,500 r/min and the thermal reference speed is 10,900 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application.
Can the NKS22-XL run directly on an ordinary shaft?
Not on a soft shaft. The NKS22-XL has no inner ring, so the 22 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead.
Reviewed & verified by the MPN Base engineering desk against source catalog HR1 2026-09-25 on 2026-09-30. Read our editorial & correction policy.