NKI30-30-TN bearing: complete specifications & equivalents
The NKI30-30-TN is a DIN 616 radial bearing sized 30 x 45 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 | 30 mm |
| Outer diameter D | 45 mm |
| Width B | 30 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | polymer (PA66 glass-fibre reinforced) |
| Basic dynamic load rating C | 40.2 kN |
| Basic static load rating C0 | 85 kN |
| Fatigue load limit Pu | 10.6 kN |
| Reference speed (thermal) | 11000 rpm |
| Limiting speed (mechanical) | 13000 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 170 g |
| Manufacturer designation | NKI 30/30 TN |
| 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 | 1.181 in |
|---|---|
| Outer diameter D | 1.772 in |
| Width B | 1.181 in |
| ISO bore code | — |
| Radial section height (D−d)/2 | 7.5 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) | 13 of 30 |
| Bore above smallest NKI-series size | 25 mm |
Cross references & equivalents
No verified interchange data yet. Send an inquiry and our team will confirm equivalents manually.
How the NKI30-30-TN model number is decoded
NKI 30/30 TN is a machined-ring needle roller bearing with an inner ring: flanged outer ring plus a separate 30 mm bore inner ring, so the shaft seat needs only ordinary tolerance, as tabulated by SKF in SKF catalogue PUB BU/P1 17000. Reading the designation: the letters name the series with inner ring, the numbers the boundary plan — 30 mm bore (d), 30 mm width; the 45 mm OD follows the dimension series, and the inner ring is a separate ground component. The 2RS executions of the 49 series carry contact seals on both faces and a wider outer ring — their B and s dimensions differ from the open execution, so housings must be re-checked before substituting. The 170 g catalogue mass and 7.5 mm radial section ((45−30)/2) frame a rating of about 1.34 kN dynamic per millimetre of bore — the needle construction's density advantage over ball bearings of the same envelope. Mounting: heat or press the inner ring onto the 30 mm k5 seat (max 120 °C), fit the flanged outer ring into the H7 housing bore, and check the 30 mm assembly for free rotation before applying load.
Typical equipment & failure modes
Common applications
- conveyor roller ends and return rollers
- agricultural implement pivots and cutter heads
- electric motor armature shafts with ground seats
- printing and paper-handling rollers
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
- corrosion pitting from condensation in intermittently operated machinery
- inner-ring bore fretting on a loose shaft seat, migrating hard particles into the rolling contact
Selection pitfalls — read before you substitute
- At 30 mm bore, verify shaft deflection against the needle length: these rollers tolerate little edge loading, and a simply supported span between 30 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: NKI 30/30 TN shares its 30×45×30 mm outline with inner-ring and sealed siblings whose ratings differ — the family letters are part of the specification, not decoration.
- The 40.2/85 kN ratings and 170 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
Which dimensions does the NKI 30/30 TN have?
A NKI 30/30 TN measures 30 mm bore/Fw × 45 mm outside diameter × 30 mm width (1.181 × 1.772 × 1.181 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 40.2 kN, static C0 85 kN, fatigue limit Pu 10.6 kN, limiting speed 13,000 r/min, reference speed 11,000 r/min, mass about 170 g.
What does NKI 30/30 TN mean in SKF part numbering?
The letters mark a machined-ring needle roller bearing with inner ring: 30 mm bore, 30 mm width, 45 mm OD per the series plan. The hardened inner ring is the raceway, so an ordinary k5 shaft seat suffices.
Does the NKI 30/30 TN need a hardened and ground shaft?
Yes — that is the point of this family. The NKI 30/30 TN carries its own hardened, ground inner ring on a 30 mm seat, so the shaft needs only a normal k5/j6 finish. The inner ring is separable and replaceable.
What mounting mistakes ruin a NKI 30/30 TN?
Mount the inner ring on the 30 mm seat first (induction heat, max 120 °C, or press), then fit the flanged outer ring into the H7 housing bore. Verify free rotation and, for 2RS executions, check the wider outer ring against the housing depth.
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.