61901-ZZ bearing: complete specifications & equivalents
The 61901-ZZ is a ISO 15 radial bearing sized 12 x 24 x 6 mm (bore x OD x width) with ZZ sealing. Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | SKF |
| Bore diameter d | 12 mm |
| Outer diameter D | 24 mm |
| Width B | 6 mm |
| Material | GCr15 |
| Seal / shield | ZZ |
| Internal clearance | CN / C3 available |
| Tolerance class | P0 |
| Cage | steel, stamped ribbon (J-type) |
| Basic dynamic load rating C | 2.91 kN |
| Basic static load rating C0 | 1.46 kN |
| Fatigue load limit Pu | 0.062 kN |
| Reference speed (thermal) | 67000 rpm |
| Limiting speed (mechanical) | 32000 rpm |
| Operating temperature | -30 to +120 °C |
| Mass | 11 g |
| Manufacturer designation | SKF 61901-2Z |
| 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 | 0.472 in |
|---|---|
| Outer diameter D | 0.945 in |
| Width B | 0.236 in |
| ISO bore code | 01 |
| Radial section height (D−d)/2 | 6 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) | 9 of 63 |
| Bore above smallest 61900-series size | 9 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| 61901-2RS-FAG | FAG | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 12×24×6 mm envelope per ISO 15; seal variant differs (ZZ vs 2RS) — confirm sealing suits the duty. |
| 61901-FAG | FAG | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 12×24×6 mm envelope per ISO 15; seal variant differs (ZZ vs OPEN) — confirm sealing suits the duty. |
| 61901-ZZ-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. |
| 61901 | ISO 15 | verify Commonly quoted cross reference; confirm against the target catalog before ordering. | ISO 15 boundary-dimension envelope; seal suffix convention varies by brand (2RS / DDU / LLU / 2RSR) — verify seal design and temperature range before substituting. |
| 61901-2RS-NSK | NSK | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 12×24×6 mm envelope per ISO 15; seal variant differs (ZZ vs 2RS) — confirm sealing suits the duty. |
| 61901-NSK | NSK | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 12×24×6 mm envelope per ISO 15; seal variant differs (ZZ vs OPEN) — confirm sealing suits the duty. |
| 61901-RSR | NSK | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 12×24×6 mm envelope per ISO 15; seal variant differs (ZZ vs RSR) — confirm sealing suits the duty. |
| 61901-ZZ-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. |
| 61901-2RS-NTN | NTN | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 12×24×6 mm envelope per ISO 15; seal variant differs (ZZ vs 2RS) — confirm sealing suits the duty. |
| 61901-NTN | NTN | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 12×24×6 mm envelope per ISO 15; seal variant differs (ZZ vs OPEN) — confirm sealing suits the duty. |
| 61901-RSR-NTN | NTN | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 12×24×6 mm envelope per ISO 15; seal variant differs (ZZ vs RSR) — confirm sealing suits the duty. |
| 61901-ZZ-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. |
| W61901-2RS | SKF | partial Main dimensions match; tolerances, seals or internal clearance differ. | SKF stainless execution W 61901-2RS1 shares the 12×24×6 mm envelope but rates differently (2.91/1.46 kN vs 2.51/1.46 kN) — not a load-rating equivalent. |
| W61901-ZZ | SKF | partial Main dimensions match; tolerances, seals or internal clearance differ. | SKF stainless execution W 61901-2Z shares the 12×24×6 mm envelope but rates differently (2.91/1.46 kN vs 2.51/1.46 kN) — not a load-rating equivalent. |
| W61901 | SKF | partial Main dimensions match; tolerances, seals or internal clearance differ. | SKF stainless execution W 61901 shares the 12×24×6 mm envelope but rates differently (2.91/1.46 kN vs 2.51/1.46 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 61901-ZZ model number is decoded
61901-ZZ carries two non-contact sheet-steel shields that hold the factory grease in and keep coarse debris out; they do not seal against liquids. Within the thin 619xx section (diameter series 9 of ISO 15), its bore code 01 comes from the 10/12/15/17 mm exception table, giving a 12 mm bore; the 24 mm outside diameter and 6 mm width follow the same boundary-dimension plan. For a rotating inner ring on a 12 mm shaft under normal load, catalogue practice seats it on a j5 shaft fit with an H7 housing bore — confirm against the actual load direction and magnitude before committing. SKF's own suffix is 2Z (this page's industry-neutral spelling is -ZZ); catalogue number 61901-2Z.
Typical equipment & failure modes
Common applications
- clutch and transmission assemblies
- robotics and automation joints
- lay shafts and idler shafts
- textile machinery
Known failure patterns
- fine-particle abrasion when non-contact shields let dust past in dirty duty
- grease aging in the shield-for-life cavity with no relubrication path
- brinelling from static overload or hammering during mounting
- false brinelling from vibration while the shaft is stationary
Selection pitfalls — read before you substitute
- Miniature bearings like 61901-ZZ (12 mm bore) brinell under surprisingly small pressing force; use a fitting sleeve on the ring being mounted and never let the assembly load cross the balls.
- The 619xx thin section at 12 mm bore (6.0 mm section height) cannot shrug off the misalignment a standard section tolerates; keep the housing bores round and aligned, or edge contact will spall the raceways early.
- Do not wash 61901-ZZ in solvent before mounting: the grease inside the shielded cavity is the service fill, and solvent creeping past the shield gap strips it out.
- Shielded 61901-ZZ units are typically greased for life; prying the shields out for regreasing usually bends them and leaves a gap that throws grease in service.
- The housing bore for the 24 mm OD should be round within IT7; an oval bore pinches the outer ring of 61901-ZZ and shows up later as two-point loaded raceway wear.
- Grease compatibility is not guaranteed between fills: mixing lithium and polyurea thickeners in a 61900-series position can soften the mixture and leak — clean out the old fill before switching grease types.
- SKF spells the shielded version 61901-2Z (one shield: 61901-Z), not "-ZZ": the suffix language differs by brand even though the ISO envelope is identical, so quote the brand designation when ordering.
- The 2.91/1.46 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 61901-ZZ bearing?
A 61901-ZZ deep-groove ball bearing has a 12 mm bore, 24 mm outer diameter and 6 mm width (0.472 × 0.945 × 0.236 in), per ISO 15 boundary dimensions. It is fitted with two non-contact metallic shields.
What lubrication does 61901-ZZ need?
61901-ZZ is greased at the factory and the shields hold the fill for the bearing's service life; relubrication is not intended, and adding grease through the shield gap usually forces dirt in with it.
Why does 61901 not follow the bore-code × 5 rule?
Codes 00–03 use the exception table (10, 12, 15 and 17 mm): 61901 with code 01 has a 12 mm bore. The code × 5 convention starts at code 04 (20 mm).
What does the ZZ suffix on 61901-ZZ mean?
ZZ means two non-contact sheet-metal shields, one each side. They retain factory grease and block coarse particles with little friction, but do not seal against liquids, fine dust or pressure washing.
What is the SKF designation and catalogue data for 61901-ZZ?
In the SKF Rolling Bearings catalogue this size is listed as 61901-2Z — two non-contact sheet-metal shields, 12×24×6 mm per ISO 15. Quoted values: C 2.91 kN, C0 1.46 kN, Pu 0.062 kN, limiting speed 32000 r/min, mass 11 g. Brand suffixes (2Z, 2RSH, 2RSL) differ from the industry-neutral spelling 61901-ZZ.
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.