RPNA25-42 bearing: complete specifications & equivalents
The RPNA25-42 is a DIN 616 radial bearing sized 25 x 42 x 20 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | SKF |
| Bore diameter d | 25 mm |
| Outer diameter D | 42 mm |
| Width B | 20 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | none |
| Basic dynamic load rating C | 19 kN |
| Basic static load rating C0 | 32.5 kN |
| Fatigue load limit Pu | 4 kN |
| Reference speed (thermal) | 16000 rpm |
| Limiting speed (mechanical) | 18000 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 110 g |
| Manufacturer designation | RPNA 25/42 |
| Standard | DIN 616 |
| Catalog version | SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.5 alignment needle roller bearings, without an inner ring |
| Last verified | 2026-09-26 |
Source: catalog reference (SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.5 alignment needle roller bearings, without 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. 7.5 alignment needle roller bearings, without 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 & RPNA-series range
| Bore d | 0.984 in |
|---|---|
| Outer diameter D | 1.654 in |
| Width B | 0.787 in |
| ISO bore code | — |
| Radial section height (D−d)/2 | 8.5 mm |
| Smallest bore in RPNA-series | 15 mm |
| Largest outer diameter in RPNA-series | 62 mm |
| Width range across RPNA-series | 12–20 mm |
| Bore position in RPNA-series (smallest first) | 4 of 8 |
| Bore above smallest RPNA-series size | 10 mm |
Cross references & equivalents
No verified interchange data yet. Send an inquiry and our team will confirm equivalents manually.
How the RPNA25-42 model number is decoded
RPNA 25/42 combines machined-ring needle roller capacity with self-alignment: 25×42×20 mm envelope, convex outer-ring outside running in a correspondingly sphered washer or housing seat. The code RPNA 25/42 reads as alignment needle roller bearing, 25 mm bore, 20 mm width — the wide section is what absorbs both load and the seat-angle errors the family is designed for. These are heavy-section machined rings, not drawn cups: the sphered outside surface is ground, the flanges retain the rollers, and the PNA execution adds the ground inner ring for unhardened shafts. Catalogue mass 110 g at 25×42×20 mm makes this one of the highest capacity-per-gram choices in the self-aligning needle roller bearings without inner ring; the limit is usually the shaft's ability to serve as a raceway, not the rolling contact itself. The sphered seat must be clean and lightly oiled — a scored seat converts the alignment feature into a friction lock, and the needle rollers then take the seat error the family was meant to absorb.
Typical equipment & failure modes
Common applications
- construction equipment blade and arm pivots
- steering knuckles and kingpin supports with seat angle errors
- pivot bearings where housing bores cannot be kept coaxial
- linkage eyes and clevis mounts on frames that flex
Known failure patterns
- raceway spalling once the catalogue L10 life is exceeded or after overload events
- 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
- brinelling of raceways from impact or pressing force transmitted through the rolling elements
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 42 mm ring or cup into a lobed shape, and the rollers then trace the housing's geometry error, not the design load.
- 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.
- 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.
- The 19/32.5 kN ratings and 110 g mass are SKF catalogue values transcribed from ch. 7.5 of PUB BU/P1 17000 (PDF table page 650); combined-type axial ratings appear in the text above because the structured record carries radial values only.
Frequently asked questions
How is the RPNA 25/42 designation read?
RPNA marks the self-aligning needle roller family (with machined rings): figures give the 25 mm seat and 20 mm width; the convex outer-ring outside surface aligns within roughly ±2° in its sphered seat.
Can the RPNA 25/42 run on an unhardened shaft?
Depends on the family member: RPNA runs directly on the shaft (hardened, 58–64 HRC, ground), while PNA includes a ground inner ring for an ordinary 25 mm k5 seat. Both add the sphered outer ring for seat misalignment.
How should the RPNA 25/42 be mounted?
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.
What limits the service life of a RPNA 25/42?
Beyond the L10 rating, the practical limits are journal/raceway hardness for the 25 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 8.5 mm radial section leaves no reserve once a raceway is dented or ribboned.
Reviewed & verified by the MPN Base engineering desk against source catalog SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.5 alignment needle roller bearings, without an inner ring on 2026-09-26. Read our editorial & correction policy.