NA4913 bearing: complete specifications & equivalents
The NA4913 is a ISO 1206 radial bearing sized 65 x 90 x 25 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | SKF |
| Bore diameter d | 65 mm |
| Outer diameter D | 90 mm |
| Width B | 25 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | none |
| Basic dynamic load rating C | 61.6 kN |
| Basic static load rating C0 | 120 kN |
| Fatigue load limit Pu | 14.6 kN |
| Reference speed (thermal) | 5600 rpm |
| Limiting speed (mechanical) | 6300 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 460 g |
| Manufacturer designation | NA 4913 |
| Standard | ISO 1206 |
| 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 & NA-49-series range
| Bore d | 2.559 in |
|---|---|
| Outer diameter D | 3.543 in |
| Width B | 0.984 in |
| ISO bore code | 13 |
| Radial section height (D−d)/2 | 12.5 mm |
| Smallest bore in NA-49-series | 10 mm |
| Largest outer diameter in NA-49-series | 190 mm |
| Width range across NA-49-series | 13–50 mm |
| Bore position in NA-49-series (smallest first) | 17 of 28 |
| Bore above smallest NA-49-series size | 55 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| NKI65-25 | SKF | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 65×90×25 mm envelope, but catalogue C/C0 differ between the executions (61.6/120 vs 52.8/106 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 NA4913 model number is decoded
For a 65 mm shaft that cannot be hardened on site, NA 4913 adds a hardened, ground inner ring to the machined needle roller design: envelope 65×90×25 mm per the dimension series 49 needle roller bearings with inner ring plan. Reading the designation: the letters name the series with inner ring, the numbers the boundary plan — 65 mm bore (d), 25 mm width; the 90 mm OD follows the dimension series, and the inner ring is a separate ground component. TN polymer cage executions run quieter and tolerate grease-lubricated pivot duty; steel cage executions remain the choice for higher temperature or oil-bath lubrication. Catalogue mass 460 g at 65×90×25 mm makes this one of the highest capacity-per-gram choices in the dimension series 49 needle roller bearings with inner ring; the limit is usually the shaft's ability to serve as a raceway, not the rolling contact itself. Mounting: heat or press the inner ring onto the 65 mm k5 seat (max 120 °C), fit the flanged outer ring into the H7 housing bore, and check the 25 mm assembly for free rotation before applying load.
Typical equipment & failure modes
Common applications
- printing and paper-handling rollers
- gearbox shafts where the journal cannot be hardened on site
- wheel and lever pivots needing a replaceable inner ring
- conveyor roller ends and return rollers
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
- abrasive paste formation from dust ingressing past open ends without effective housing seals
- rolling-contact fatigue spalling after the rated L10 life
- inner-ring raceway spalling after the narrow ring section runs hot with excessive interference
Selection pitfalls — read before you substitute
- Above 50 mm bore, thermal growth matters: the 65 mm inner ring or journal grows with temperature faster than the housing, and the small clearance of a needle roller contact leaves little reserve — check running clearance hot, not just at assembly.
- The quoted 61.6/120 kN ratings are SKF catalogue values for this exact execution (NA 4913); 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.
- The 61.6/120 kN ratings and 460 g mass are SKF catalogue values transcribed from ch. 7.4 of PUB BU/P1 17000 (PDF table page 644); combined-type axial ratings appear in the text above because the structured record carries radial values only.
Frequently asked questions
Which dimensions does the NA 4913 have?
A NA 4913 measures 65 mm bore/Fw × 90 mm outside diameter × 25 mm width (2.559 × 3.543 × 0.984 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 61.6 kN, static C0 120 kN, fatigue limit Pu 14.6 kN, limiting speed 6,300 r/min, reference speed 5,600 r/min, mass about 460 g.
What does NA 4913 mean in SKF part numbering?
The letters mark a machined-ring needle roller bearing with inner ring: 65 mm bore, 25 mm width, 90 mm OD per the series plan. The hardened inner ring is the raceway, so an ordinary k5 shaft seat suffices.
Does the NA 4913 need a hardened and ground shaft?
Yes — that is the point of this family. The NA 4913 carries its own hardened, ground inner ring on a 65 mm seat, so the shaft needs only a normal k5/j6 finish. The inner ring is separable and replaceable.
What mounting mistakes ruin a NA 4913?
Mount the inner ring on the 65 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.