NA4915 bearing: complete specifications & equivalents
The NA4915 is a ISO 1206 radial bearing sized 75 x 105 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 | 75 mm |
| Outer diameter D | 105 mm |
| Width B | 30 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | none |
| Basic dynamic load rating C | 84.2 kN |
| Basic static load rating C0 | 170 kN |
| Fatigue load limit Pu | 21.6 kN |
| Reference speed (thermal) | 4800 rpm |
| Limiting speed (mechanical) | 5300 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 780 g |
| Manufacturer designation | NA 4915 |
| 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 | 2.953 in |
|---|---|
| Outer diameter D | 4.134 in |
| Width B | 1.181 in |
| ISO bore code | 15 |
| Radial section height (D−d)/2 | 15 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) | 19 of 28 |
| Bore above smallest NA-49-series size | 65 mm |
Cross references & equivalents
No verified interchange data yet. Send an inquiry and our team will confirm equivalents manually.
How the NA4915 model number is decoded
The dimension series 49 needle roller bearings with inner ring execution NA 4915 measures 75×105×30 mm: needle rollers caged between a flanged outer ring and a ground inner ring, used wherever the journal cannot serve as a raceway. In SKF nomenclature the leading letters mark a machined-ring needle bearing with inner ring: figures state 75 mm d and 30 mm B, the 105 mm outside diameter from the dimension series 49 needle roller bearings with inner ring, and the 2RS suffix would add contact seals. 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 780 g at 75×105×30 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 75 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
- 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 75 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.
- Reference and limiting speeds are different limits: the 4,800 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 75 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.
- The 84.2/170 kN ratings and 780 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
What mounting mistakes ruin a NA 4915?
Mount the inner ring on the 75 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.
Is the NA 4915 sealed?
No — the open execution relies on housing seals; 2RS executions of the 49 series add contact seals with a wider outer ring as a separate order number.
Which dimensions does the NA 4915 have?
A NA 4915 measures 75 mm bore/Fw × 105 mm outside diameter × 30 mm width (2.953 × 4.134 × 1.181 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 84.2 kN, static C0 170 kN, fatigue limit Pu 21.6 kN, limiting speed 5,300 r/min, reference speed 4,800 r/min, mass about 780 g.
What does NA 4915 mean in SKF part numbering?
The letters mark a machined-ring needle roller bearing with inner ring: 75 mm bore, 30 mm width, 105 mm OD per the series plan. The hardened inner ring is the raceway, so an ordinary k5 shaft seat suffices.
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.