NKXR45-Z bearing: complete specifications & equivalents
The NKXR45-Z is a DIN 616 radial bearing sized 45 x 58 x 32 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | SKF |
| Bore diameter d | 45 mm |
| Outer diameter D | 58 mm |
| Width B | 32 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | none |
| Basic dynamic load rating C | 27.5 kN |
| Basic static load rating C0 | 57 kN |
| Fatigue load limit Pu | 7.1 kN |
| Reference speed (thermal) | 2200 rpm |
| Limiting speed (mechanical) | 4500 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 260 g |
| Manufacturer designation | NKXR 45 Z |
| Standard | DIN 616 |
| Catalog version | SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.10 needle roller / cylindrical-needle thrust |
| Last verified | 2026-09-26 |
Source: catalog reference (SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.10 needle roller / cylindrical-needle thrust) · extracted 2026-09-26
Parameters extracted from the official SKF Rolling Bearings catalogue (SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.10 needle roller / cylindrical-needle thrust); 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 & NKXR-series range
| Bore d | 1.772 in |
|---|---|
| Outer diameter D | 2.283 in |
| Width B | 1.26 in |
| ISO bore code | — |
| Radial section height (D−d)/2 | 6.5 mm |
| Smallest bore in NKXR-series | 15 mm |
| Largest outer diameter in NKXR-series | 62 mm |
| Width range across NKXR-series | 23–35 mm |
| Bore position in NKXR-series (smallest first) | 8 of 9 |
| Bore above smallest NKXR-series size | 30 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| NKXR45 | SKF | full Dimensions and internal design equivalent — standard interchange. | Same 45×58×32 mm envelope and equivalent catalogue ratings; NKXR45 is the combined needle/thrust needle execution — boundary-dimension interchangeable, execution differences (seals, shields, cage) apply. |
| NKX45-Z | SKF | full Dimensions and internal design equivalent — standard interchange. | Envelope-identical (45×58×32 mm) combined needle/thrust ball execution with ratings within 10 % — substitution possible after checking ring/flange construction. |
| NKX45 | SKF | full Dimensions and internal design equivalent — standard interchange. | Envelope-identical (45×58×32 mm) combined needle/thrust ball execution with ratings within 10 % — substitution possible after checking ring/flange construction. |
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 NKXR45-Z model number is decoded
NKXR 45 Z is a combined needle roller / full complement needle thrust bearing: caged needle rollers for radial duty plus a packed needle thrust set for the highest axial capacity of any 45 mm combined bearing, per SKF catalogue PUB BU/P1 17000 ch. 7.10. Reading the designation: NKXR marks needle roller + full complement needle thrust, the number the 45 mm shaft seat; 58 mm OD and 32 mm height follow the series plan. Thrust needle sets tolerate slow speeds and heavy loads: the 4,500 r/min limiting speed is far below ball-thrust equivalents, and lubricant film at the washer faces governs life. The minimum load factor A 0.0019 applies to the thrust part: below that axial load the rolling elements of the thrust set skid, so springs or preload washers are part of the arrangement, not an afterthought. Fit with a press against the washer faces only — needles packed without a cage will skew if the assembly is dropped or driven sideways onto the 45 mm seat.
Typical equipment & failure modes
Common applications
- large valve stems under high axial load
- turntables and slewing pivots with shock loads
- press-fit die set guide positions
- heavy screw presses and clamping spindles
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
- false brinelling of standby equipment under external vibration
- thrust-part ball or roller skidding and smearing when the axial load falls below the minimum factor
Selection pitfalls — read before you substitute
- At 45 mm bore, verify shaft deflection against the needle length: these rollers tolerate little edge loading, and a simply supported span between 45 mm seats can bend past the compensation range long before the load rating is exhausted.
- Contamination, not fatigue, kills most small needle bearings: with raceways this narrow, one hard particle dents a full-width line — seal the housing even when the bearing execution itself is open.
- Do not interchange envelope-identical needle families blindly: NKXR 45 Z shares its 45×58×32 mm outline with inner-ring and sealed siblings whose ratings differ — the family letters are part of the specification, not decoration.
- Do not treat the axial rating 45 kN (Ca) as independent of radial load: the combined equivalent load formulas couple them, and a unit sized on radial life alone will spall the ball raceway first under real thrust.
- The thrust part is one-direction: reverse axial events — however brief — lift the rolling elements off the raceway, and the subsequent re-entry impact dents the washer face; mount the NKXR 45 Z facing the working thrust.
- The 27.5/57 kN ratings and 260 g mass are SKF catalogue values transcribed from ch. 7.10 of PUB BU/P1 17000 (PDF table page 660); combined-type axial ratings appear in the text above because the structured record carries radial values only.
Frequently asked questions
What does NKXR 45 Z mean in SKF part numbering?
NKXR = needle roller radial part + full complement needle thrust part for a 45 mm shaft: 58 mm OD, 32 mm overall height, the highest axial rating of the combined needle families.
Does the NKXR 45 Z need a hardened and ground shaft?
The radial needle part of the NKXR 45 Z runs directly on the 45 mm journal — harden to 58–64 HRC and grind it. The thrust washers are integral, so no separate inner ring exists; size the shaft for the raceway tolerances in the catalogue table.
What mounting mistakes ruin a NKXR 45 Z?
Press on the ring faces only with a fitting sleeve, keep everything square to the 45 mm seat, and never transmit force through the rolling elements. Follow the catalogue's seat tolerances — the narrow needle contact forgives neither tilt nor burrs.
Is the NKXR 45 Z sealed?
No — this execution is open and depends on the housing sealing arrangement; grease it at assembly and keep the relubrication interval short in dirty duty.
Reviewed & verified by the MPN Base engineering desk against source catalog SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.10 needle roller / cylindrical-needle thrust on 2026-09-26. Read our editorial & correction policy.