NX25 bearing: complete specifications & equivalents

The NX25 is a DIN 616 radial bearing sized 25 x 37 x 30 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.

Principal dimensions: bore d 25 mm, outer diameter D 37 mm, width B 30 mm. Schematic, not to scale.

Specification table

Parameter	Value
Brand	SKF
Bore diameter d	25 mm
Outer diameter D	37 mm
Width B	30 mm
Material	GCr15
Seal / shield	open
Internal clearance	CN
Tolerance class	P0
Cage	none
Basic dynamic load rating C	15.1 kN
Basic static load rating C0	24.5 kN
Fatigue load limit Pu	2.9 kN
Reference speed (thermal)	5600 rpm
Limiting speed (mechanical)	6300 rpm
Operating temperature	-40 to +120 °C
Mass	120 g
Manufacturer designation	NX 25
Standard	DIN 616
Catalog version	SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.8 needle roller / thrust ball, full complement thrust part
Last verified	2026-09-26

Source: catalog reference (SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.8 needle roller / thrust ball, full complement thrust part) · extracted 2026-09-26

Parameters extracted from the official SKF Rolling Bearings catalogue (SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.8 needle roller / thrust ball, full complement thrust part); 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 & NX-series range

Bore d	0.984 in
Outer diameter D	1.457 in
Width B	1.181 in
ISO bore code	—
Radial section height (D−d)/2	6 mm
Smallest bore in NX-series	7 mm
Largest outer diameter in NX-series	47 mm
Width range across NX-series	18–30 mm
Bore position in NX-series (smallest first)	7 of 9
Bore above smallest NX-series size	18 mm

Cross references & equivalents

Equivalent model	Brand	Match level	Note
NX25-Z	SKF	full Dimensions and internal design equivalent — standard interchange.	Same 25×37×30 mm envelope and equivalent catalogue ratings; NX25-Z is the combined needle/thrust ball execution — boundary-dimension interchangeable, execution differences (seals, shields, cage) apply.
RNA6904	SKF	partial Main dimensions match; tolerances, seals or internal clearance differ.	Same 25×37×30 mm envelope, but catalogue C/C0 differ between the executions (15.1/24.5 vs 35.2/53 kN) — boundary dimensions match, not a load-rating equivalent.
NKX25-Z	SKF	partial Main dimensions match; tolerances, seals or internal clearance differ.	Same 25×37×30 mm envelope, but catalogue C/C0 differ between the executions (15.1/24.5 vs 19/32.5 kN) — boundary dimensions match, not a load-rating equivalent.
NKX25	SKF	partial Main dimensions match; tolerances, seals or internal clearance differ.	Same 25×37×30 mm envelope, but catalogue C/C0 differ between the executions (15.1/24.5 vs 19/32.5 kN) — boundary dimensions match, not a load-rating equivalent.
NKXR25	SKF	partial Main dimensions match; tolerances, seals or internal clearance differ.	Same 25×37×30 mm envelope, but catalogue C/C0 differ between the executions (15.1/24.5 vs 19/32.5 kN) — boundary dimensions match, not a load-rating equivalent.
NKXR25-Z	SKF	partial Main dimensions match; tolerances, seals or internal clearance differ.	Same 25×37×30 mm envelope, but catalogue C/C0 differ between the executions (15.1/24.5 vs 19/32.5 kN) — boundary dimensions match, not a load-rating equivalent.

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 NX25 model number is decoded

The combined needle roller / full complement thrust ball bearings execution NX 25 measures 25×37×30 mm: radial duty on caged needle rollers, axial duty on a full complement of thrust balls rated 12.4 kN (Ca), both in one shaft position. Reading the designation: NX marks needle roller + full complement thrust ball, the number the 25 mm shaft seat; 37 mm OD and 30 mm overall height follow the series plan. Full complement thrust parts run slower than caged ones: observe the 6,300 r/min limiting speed, and expect the thrust part to govern the thermal ceiling. Selection arithmetic for the combined unit: radial C 15.1 kN, radial C0 24.5 kN, axial dynamic 12.4 kN (Ca) and axial static 28.5 kN (C0a); combine them with the equivalent-load factors from the catalogue before checking L10. Check after fitting that the radial needle cage and the thrust part rotate independently where the design allows; binding between the two indicates a bent washer or a stray ball.

Typical equipment & failure modes

Common applications

screw jack and lifting screw spindles
valve and dosing pump stems with slow axial push
light rotary tables under axial load
oscillating pivots with steady axial preload

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
grease starvation at the roller ends when relubrication intervals are stretched in dirty duty
hard-particle indentation in unfiltered lubricant
thrust washer raceway wear from reverse axial shocks the one-direction thrust part cannot carry

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 37 mm ring or cup into a lobed shape, and the rollers then trace the housing's geometry error, not the design load.
The quoted 15.1/24.5 kN ratings are SKF catalogue values for this exact execution (NX 25); ratings can be revised without the order number changing, so keep the catalogue version (SKF catalogue PUB BU/P1 17000) with the drawing.
Oscillating pivots fail differently: rocking through a small angle concentrates wear in the same roller positions — inspect those zones, and consider rotating the assembly's clock position at service intervals.
Height stack-up is easy to mis-check: the thrust-washer 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 12.4 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 15.1/24.5 kN ratings and 120 g mass are SKF catalogue values transcribed from ch. 7.8 of PUB BU/P1 17000 (PDF table page 656); combined-type axial ratings appear in the text above because the structured record carries radial values only.

Frequently asked questions

Does the NX 25 need a hardened and ground shaft?

The radial needle part of the NX 25 runs directly on the 25 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 NX 25?

Press on the ring faces only with a fitting sleeve, keep everything square to the 25 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 NX 25 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 NX 25 have?

A NX 25 measures 25 mm bore/Fw × 37 mm outside diameter × 30 mm width (0.984 × 1.457 × 1.181 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 15.1 kN, static C0 24.5 kN, fatigue limit Pu 2.9 kN, limiting speed 6,300 r/min, reference speed 5,600 r/min, mass about 120 g. Axial ratings of the thrust part: dynamic Ca 12.4 kN (Ca), static C0a 28.5 kN (C0a), minimum load factor A 0.0042; the thrust set carries load in one direction only.

Reviewed & verified by the MPN Base engineering desk against source catalog SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.8 needle roller / thrust ball, full complement thrust part on 2026-09-26. Read our editorial & correction policy.