NA4907-2RS bearing: complete specifications & equivalents
The NA4907-2RS is a ISO 1206 radial bearing sized 35 x 55 x 21 mm (bore x OD x width) with 2RS sealing. Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | SKF |
| Bore diameter d | 35 mm |
| Outer diameter D | 55 mm |
| Width B | 21 mm |
| Material | GCr15 |
| Seal / shield | 2RS |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | none |
| Basic dynamic load rating C | 27 kN |
| Basic static load rating C0 | 43 kN |
| Fatigue load limit Pu | 5.3 kN |
| Limiting speed (mechanical) | 4800 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 180 g |
| Manufacturer designation | NA 4907.2RS |
| 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 | 1.378 in |
|---|---|
| Outer diameter D | 2.165 in |
| Width B | 0.827 in |
| ISO bore code | 07 |
| Radial section height (D−d)/2 | 10 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) | 11 of 28 |
| Bore above smallest NA-49-series size | 25 mm |
Cross references & equivalents
No verified interchange data yet. Send an inquiry and our team will confirm equivalents manually.
How the NA4907-2RS model number is decoded
NA 4907.2RS provides the full machined-ring needle roller construction: ground inner ring on a 35 mm seat, flanged outer ring at 55 mm, caged needles between them — the standard choice when a replaceable inner raceway is required. In SKF nomenclature the leading letters mark a machined-ring needle bearing with inner ring: figures state 35 mm d and 21 mm B, the 55 mm outside diameter from the dimension series 49 needle roller bearings with inner ring, and the 2RS suffix would add contact seals. 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. For life calculation, the 27/43 kN ratings assume raceway geometry supplied by the shaft and housing in families without an inner ring — journal hardness, roundness and finish are part of the bearing, not of the application. Because the inner ring is separable, mount it first against its shoulder, then slide the outer ring and roller set over it — the order avoids forcing rollers across the shaft threads or burrs.
Typical equipment & failure modes
Common applications
- agricultural implement pivots and cutter heads
- electric motor armature shafts with ground seats
- printing and paper-handling rollers
- gearbox shafts where the journal cannot be hardened on site
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
- false brinelling of standby equipment under external vibration
- inner-ring raceway spalling after the narrow ring section runs hot with excessive interference
Selection pitfalls — read before you substitute
- At 35 mm bore, verify shaft deflection against the needle length: these rollers tolerate little edge loading, and a simply supported span between 35 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: NA 4907.2RS shares its 35×55×21 mm outline with inner-ring and sealed siblings whose ratings differ — the family letters are part of the specification, not decoration.
- The 27/43 kN ratings and 180 g mass are SKF catalogue values transcribed from ch. 7.4 of PUB BU/P1 17000 (PDF table page 642); 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 4907.2RS have?
A NA 4907.2RS measures 35 mm bore/Fw × 55 mm outside diameter × 21 mm width (1.378 × 2.165 × 0.827 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 27 kN, static C0 43 kN, fatigue limit Pu 5.3 kN, limiting speed 4,800 r/min, mass about 180 g.
What does NA 4907.2RS mean in SKF part numbering?
The letters mark a machined-ring needle roller bearing with inner ring: 35 mm bore, 21 mm width, 55 mm OD per the series plan. The hardened inner ring is the raceway, so an ordinary k5 shaft seat suffices.
Does the NA 4907.2RS need a hardened and ground shaft?
Yes — that is the point of this family. The NA 4907.2RS carries its own hardened, ground inner ring on a 35 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 4907.2RS?
Mount the inner ring on the 35 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.