RPNA18-32 bearing: complete specifications & equivalents
The RPNA18-32 is a DIN 616 radial bearing sized 18 x 32 x 16 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | SKF |
| Bore diameter d | 18 mm |
| Outer diameter D | 32 mm |
| Width B | 16 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | none |
| Basic dynamic load rating C | 12.8 kN |
| Basic static load rating C0 | 17.6 kN |
| Fatigue load limit Pu | 2.12 kN |
| Reference speed (thermal) | 22000 rpm |
| Limiting speed (mechanical) | 24000 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 52 g |
| Manufacturer designation | RPNA 18/32 |
| 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 | 0.709 in |
|---|---|
| Outer diameter D | 1.26 in |
| Width B | 0.63 in |
| ISO bore code | — |
| Radial section height (D−d)/2 | 7 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) | 2 of 8 |
| Bore above smallest RPNA-series size | 3 mm |
Cross references & equivalents
No verified interchange data yet. Send an inquiry and our team will confirm equivalents manually.
How the RPNA18-32 model number is decoded
RPNA 18/32 is a self-aligning needle roller bearing: a heavy machined outer ring with a convex outside surface seated against an aligning ring, absorbing housing misalignment around a 18 mm raceway, as listed in SKF catalogue PUB BU/P1 17000. Reading the designation: RPNA marks the self-aligning execution ( inner ring), the numbers giving 18 mm bore and 16 mm width; the sphered outside diameter 32 mm follows the series plan. The alignment range is meant for static seat errors, not continuous swivelling under load — dynamic pivoting races the sphered surface and requires grease with extreme-pressure additives. Catalogue mass 52 g at 18×32×16 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. Retain the ring axially with washers spanning the full outside surface; point clamps that dig into the sphered surface flatten it and spoil the alignment travel.
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
- 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
- grease starvation at the roller ends when relubrication intervals are stretched in dirty duty
- electrical erosion on VFD-driven shafts without brush or insulated mounting
Selection pitfalls — read before you substitute
- On a 18 mm seat the housing bore quality dominates life: a bore 0.02 mm out of round pinches the 32 mm ring or cup into a lobed shape, and the rollers then trace the housing's geometry error, not the design load.
- The quoted 12.8/17.6 kN ratings are SKF catalogue values for this exact execution (RPNA 18/32); 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 12.8/17.6 kN ratings and 52 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
Does the RPNA 18/32 need a hardened and ground 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 18 mm k5 seat. Both add the sphered outer ring for seat misalignment.
What mounting mistakes ruin a RPNA 18/32?
Press on the ring faces only with a fitting sleeve, keep everything square to the 18 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.
Is the RPNA 18/32 sealed?
No — this execution is open and depends on the housing sealing arrangement; grease it at assembly and keep the relubrication interval short in dirty duty.
Which dimensions does the RPNA 18/32 have?
A RPNA 18/32 measures 18 mm bore/Fw × 32 mm outside diameter × 16 mm width (0.709 × 1.26 × 0.63 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 12.8 kN, static C0 17.6 kN, fatigue limit Pu 2.12 kN, limiting speed 24,000 r/min, reference speed 22,000 r/min, mass about 52 g.
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.