NKIA5908 bearing: complete specifications & equivalents
The NKIA5908 is a DIN 616 radial bearing sized 40 x 62 x 30 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | SKF |
| Bore diameter d | 40 mm |
| Outer diameter D | 62 mm |
| Width B | 30 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | none |
| Basic dynamic load rating C | 42.9 kN |
| Basic static load rating C0 | 71 kN |
| Fatigue load limit Pu | 8.8 kN |
| Reference speed (thermal) | 8000 rpm |
| Limiting speed (mechanical) | 9500 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 320 g |
| Manufacturer designation | NKIA 5908 |
| 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 | 1.575 in |
|---|---|
| Outer diameter D | 2.441 in |
| Width B | 1.181 in |
| ISO bore code | 08 |
| Radial section height (D−d)/2 | 11 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) | 9 of 15 |
| Bore above smallest NKIA-series size | 28 mm |
Cross references & equivalents
No verified interchange data yet. Send an inquiry and our team will confirm equivalents manually.
How the NKIA5908 model number is decoded
NKIA 5908 is a combined needle roller / angular ball bearing: one unit carrying radial load on the needle roller set and one-direction-leaning axial load on the ball set, 40×62×30 mm, listed by SKF in SKF catalogue PUB BU/P1 17000. Reading the designation: the letters combine the needle roller family with the ball execution — NKIA marks angular contact — and 595908 the heavy 59 dimension series around the 40 mm bore. NKIB three-point contact ball raceways accept axial load in both directions, while NKIA angular contact ball raceways lean the axial capacity toward one direction — check the load direction before ordering either. Selection arithmetic for the combined unit: radial C 42.9 kN, radial C0 71 kN, axial dynamic 7.17 kN (Ca) and axial static 10.9 kN (C0a); combine them with the equivalent-load factors from the catalogue before checking L10. 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
- needle edge loading and raceway denting when the shaft deflects beyond the compensation range
- 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
- brinelling of raceways from impact or pressing force transmitted through the rolling elements
- thrust-part ball or roller skidding and smearing when the axial load falls below the minimum factor
Selection pitfalls — read before you substitute
- At 40 mm bore, verify shaft deflection against the needle length: these rollers tolerate little edge loading, and a simply supported span between 40 mm seats can bend past the compensation range long before the load rating is exhausted.
- Reference and limiting speeds are different limits: the 8,000 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 40 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.
- 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.
- Do not treat the axial rating 7.17 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 42.9/71 kN ratings and 320 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
Does the NKIA 5908 need a hardened and ground shaft?
The needle roller part of the NKIA 5908 rides directly on the 40 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.
What mounting mistakes ruin a NKIA 5908?
Press on the ring faces only with a fitting sleeve, keep everything square to the 40 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 NKIA 5908 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.
Which dimensions does the NKIA 5908 have?
A NKIA 5908 measures 40 mm bore/Fw × 62 mm outside diameter × 30 mm width (1.575 × 2.441 × 1.181 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 42.9 kN, static C0 71 kN, fatigue limit Pu 8.8 kN, limiting speed 9,500 r/min, reference speed 8,000 r/min, mass about 320 g. Axial ratings of the ball part: dynamic Ca 7.17 kN (Ca), static C0a 10.9 kN (C0a); angular contact geometry leans axial capacity toward one direction.
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.