61906 bearing: complete specifications & equivalents
The 61906 is a ISO 15 radial bearing sized 30 x 47 x 9 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | SKF |
| Bore diameter d | 30 mm |
| Outer diameter D | 47 mm |
| Width B | 9 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN / C3 available |
| Tolerance class | P0 |
| Cage | steel, stamped ribbon (J-type) |
| Basic dynamic load rating C | 7.28 kN |
| Basic static load rating C0 | 4.55 kN |
| Fatigue load limit Pu | 0.212 kN |
| Reference speed (thermal) | 30000 rpm |
| Limiting speed (mechanical) | 19000 rpm |
| Operating temperature | -40 to +150 °C |
| Mass | 49 g |
| Manufacturer designation | SKF 61906 |
| Standard | ISO 15 |
| Catalog version | SKF PUB BU/P1 17000/1 EN (Oct 2018) |
| Last verified | 2026-09-25 |
Source: catalog reference (SKF PUB BU/P1 17000/1 EN (Oct 2018)) · extracted 2026-09-24
Parameters extracted from the official SKF Rolling Bearings catalogue (SKF PUB BU/P1 17000/1 EN (Oct 2018)); 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 & 61900-series range
| Bore d | 1.181 in |
|---|---|
| Outer diameter D | 1.85 in |
| Width B | 0.354 in |
| ISO bore code | 06 |
| Radial section height (D−d)/2 | 8.5 mm |
| Smallest bore in 61900-series | 3 mm |
| Largest outer diameter in 61900-series | 1120 mm |
| Width range across 61900-series | 3–118 mm |
| Bore position in 61900-series (smallest first) | 14 of 63 |
| Bore above smallest 61900-series size | 27 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| 61906-2RS-FAG | FAG | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 30×47×9 mm envelope per ISO 15; seal variant differs (OPEN vs 2RS) — confirm sealing suits the duty. |
| 61906-FAG | FAG | full Dimensions and internal design equivalent — standard interchange. | Identical ISO 15 envelope, seal and ratings band — standard interchange; re-verify precision class and clearance per supplier. |
| 61906-ZZ-FAG | FAG | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 30×47×9 mm envelope per ISO 15; seal variant differs (OPEN vs ZZ) — confirm sealing suits the duty. |
| 61906-2RS-NSK | NSK | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 30×47×9 mm envelope per ISO 15; seal variant differs (OPEN vs 2RS) — confirm sealing suits the duty. |
| 61906-NSK | NSK | full Dimensions and internal design equivalent — standard interchange. | Identical ISO 15 envelope, seal and ratings band — standard interchange; re-verify precision class and clearance per supplier. |
| 61906-RSR-NSK | NSK | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 30×47×9 mm envelope per ISO 15; seal variant differs (OPEN vs RSR) — confirm sealing suits the duty. |
| 61906-ZZ | NSK | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 30×47×9 mm envelope per ISO 15; seal variant differs (OPEN vs ZZ) — confirm sealing suits the duty. |
| 61906-2RS-NTN | NTN | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 30×47×9 mm envelope per ISO 15; seal variant differs (OPEN vs 2RS) — confirm sealing suits the duty. |
| 61906-NTN | NTN | full Dimensions and internal design equivalent — standard interchange. | Identical ISO 15 envelope, seal and ratings band — standard interchange; re-verify precision class and clearance per supplier. |
| 61906-RSR-NTN | NTN | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 30×47×9 mm envelope per ISO 15; seal variant differs (OPEN vs RSR) — confirm sealing suits the duty. |
| 61906-ZZ-NTN | NTN | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 30×47×9 mm envelope per ISO 15; seal variant differs (OPEN vs ZZ) — confirm sealing suits the duty. |
| W61906-2RS | SKF | partial Main dimensions match; tolerances, seals or internal clearance differ. | SKF stainless execution W 61906-2RS1 shares the 30×47×9 mm envelope but rates differently (7.28/4.55 kN vs 6.24/5 kN) — not a load-rating equivalent. |
| W61906 | SKF | partial Main dimensions match; tolerances, seals or internal clearance differ. | SKF stainless execution W 61906 shares the 30×47×9 mm envelope but rates differently (7.28/4.55 kN vs 6.24/5 kN) — 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 61906 model number is decoded
61906 is supplied open, without shields or seals, so the arrangement around it must supply and retain the lubricant. Within the thin 619xx section (diameter series 9 of ISO 15), multiplying bore code 06 by five gives the 30 mm bore; the 47 mm outside diameter and 9 mm width follow the same boundary-dimension plan. For a rotating inner ring on a 30 mm shaft under normal load, catalogue practice seats it on a k5 shaft fit with an H7 housing bore — confirm against the actual load direction and magnitude before committing. In the SKF catalogue this open execution carries the bare designation; protected variants are ordered separately as -2Z and -2RSH.
Typical equipment & failure modes
Common applications
- textile machinery
- packaging machinery
- space-constrained gearboxes
- clutch and transmission assemblies
Known failure patterns
- contamination wear from dust and dirt ingress through the open arrangement
- lubricant starvation when no regreasing interval is maintained
- raceway smearing under marginal lubrication at start-up
- edge loading from shaft deflection or housing misalignment
Selection pitfalls — read before you substitute
- A 30 mm shaft for 61906 should be finished to Ra ≤ 1.6 µm with square seating faces; at this bore a scored or oval journal shows up directly as running noise and early raceway damage.
- The 619xx thin section (8.5 mm section height at 30 mm bore) trades load capacity for compactness; stiff, accurately aligned seats are essential or edge loading will spall the raceway early.
- The open 61906 has no lubricant retention: grease escapes and contaminants migrate straight into the 30×47×9 mm raceway, so specify a sealed arrangement for dusty or washdown duty.
- Open bearings tolerate the highest speeds in the 61900-series but need a defined regreasing interval; run-to-failure lubrication is the dominant cause of early failure in open 61906 units.
- Do not quieten a noisy bearing by preloading it: the 61900-series is a deep-groove design, not angular-contact; axial preload raises temperature and shortens grease life.
- Vibration during standstill brinells the raceways of a 30 mm bearing at ball spacing; if the machine sits idle next to running equipment, turn the shaft over periodically or isolate the arrangement.
- The open 61906 needs external sealing and application-supplied lubrication; in the SKF catalogue the protected variants are separate order numbers 61906-2Z (shields) and 61906-2RSH (contact seals), not suffix-free 61906.
- The 7.28/4.55 kN ratings here are SKF Explorer-class figures from catalogue PUB BU/P1 17000/1 EN (Oct 2018); SKF can revise internal geometry and ratings without changing the designation, so treat the catalogue version and date as part of the specification and re-verify for critical drives.
Frequently asked questions
What are the dimensions of a 61906 bearing?
A 61906 deep-groove ball bearing has a 30 mm bore, 47 mm outer diameter and 9 mm width (1.181 × 1.85 × 0.354 in), per ISO 15 boundary dimensions. It is an open bearing with no seals or shields.
What internal clearance does 61906 have?
Unless a clearance suffix says otherwise, 61906 is manufactured to normal (CN) radial internal clearance. Tight fits and hot shafts consume clearance in service — for those conditions order the C3 execution of 61906 and verify the residual clearance after mounting.
How should 61906 be mounted?
Apply the mounting force to the ring being fitted: on a 30 mm shaft seat the press load must pass through the inner-ring face only. A fitting sleeve and an arbor press are normally sufficient at this size. Never strike the outer ring, the cage or the seals.
What lubrication does 61906 need?
The open 61906 is lubricated by the application; a NLGI 2 lithium-soap grease filled to roughly 25–35% of the free volume is the common choice, with a defined relubrication interval.
What is the SKF designation and catalogue data for 61906?
In the SKF Rolling Bearings catalogue this size is listed as 61906 — the open (unsealed) execution, 30×47×9 mm per ISO 15. Quoted values: C 7.28 kN, C0 4.55 kN, Pu 0.212 kN, limiting speed 19000 r/min, mass 49 g. Brand suffixes (2Z, 2RSH, 2RSL) differ from the industry-neutral spelling 61906.
Reviewed & verified by the MPN Base engineering desk against source catalog SKF PUB BU/P1 17000/1 EN (Oct 2018) on 2026-09-25. Read our editorial & correction policy.