61801-ZZ bearing: complete specifications & equivalents
The 61801-ZZ is a ISO 15 radial bearing sized 12 x 21 x 5 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 | 21 mm |
| Width B | 5 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 | 1.74 kN |
| Basic static load rating C0 | 0.915 kN |
| Fatigue load limit Pu | 0.039 kN |
| Reference speed (thermal) | 70000 rpm |
| Limiting speed (mechanical) | 36000 rpm |
| Operating temperature | -30 to +120 °C |
| Mass | 6 g |
| Manufacturer designation | SKF 61801-2Z |
| Standard | ISO 15 |
| Catalog version | SKF PUB BU/P1 17000/1 EN (Oct 2018) |
| Last verified | 2026-09-24 |
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 & 61800-series range
| Bore d | 0.472 in |
|---|---|
| Outer diameter D | 0.827 in |
| Width B | 0.197 in |
| ISO bore code | 01 |
| Radial section height (D−d)/2 | 4.5 mm |
| Smallest bore in 61800-series | 1 mm |
| Largest outer diameter in 61800-series | 1820 mm |
| Width range across 61800-series | 1–140 mm |
| Bore position in 61800-series (smallest first) | 12 of 74 |
| Bore above smallest 61800-series size | 11 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| 61801-2RS-FAG | FAG | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 12×21×5 mm envelope per ISO 15; seal variant (ZZ vs 2RS) and load ratings differ — confirm sealing and rating before substituting. |
| 61801-FAG | FAG | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 12×21×5 mm envelope per ISO 15; seal variant (ZZ vs OPEN) and load ratings differ — confirm sealing and rating before substituting. |
| 61801-ZZ-FAG | FAG | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 12×21×5 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting. |
| 61801 | 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. |
| 61801-2RS-NSK | NSK | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 12×21×5 mm envelope per ISO 15; seal variant (ZZ vs 2RS) and load ratings differ — confirm sealing and rating before substituting. |
| 61801-NSK | NSK | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 12×21×5 mm envelope per ISO 15; seal variant (ZZ vs OPEN) and load ratings differ — confirm sealing and rating before substituting. |
| 61801-RSR | NSK | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 12×21×5 mm envelope per ISO 15; seal variant (ZZ vs RSR) and load ratings differ — confirm sealing and rating before substituting. |
| 61801-ZZ-NSK | NSK | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 12×21×5 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting. |
| 61801-2RS-NTN | NTN | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 12×21×5 mm envelope per ISO 15; seal variant (ZZ vs 2RS) and load ratings differ — confirm sealing and rating before substituting. |
| 61801-NTN | NTN | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 12×21×5 mm envelope per ISO 15; seal variant (ZZ vs OPEN) and load ratings differ — confirm sealing and rating before substituting. |
| 61801-RSR-NTN | NTN | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 12×21×5 mm envelope per ISO 15; seal variant (ZZ vs RSR) and load ratings differ — confirm sealing and rating before substituting. |
| 61801-ZZ-NTN | NTN | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 12×21×5 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting. |
| W61801-2RS | SKF | partial Main dimensions match; tolerances, seals or internal clearance differ. | SKF stainless execution W 61801-2RS1 shares the 12×21×5 mm envelope but rates differently (1.74/0.915 kN vs 1.51/0.9 kN) — not a load-rating equivalent. |
| W61801-ZZ | SKF | partial Main dimensions match; tolerances, seals or internal clearance differ. | SKF stainless execution W 61801-2Z shares the 12×21×5 mm envelope but rates differently (1.74/0.915 kN vs 1.51/0.9 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 61801-ZZ model number is decoded
61801-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 extra-thin 618xx section (diameter series 8 of ISO 15), its bore code 01 comes from the 10/12/15/17 mm exception table, giving a 12 mm bore; the 21 mm outside diameter and 5 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 61801-2Z.
Typical equipment & failure modes
Common applications
- lay shafts and idler shafts
- textile machinery
- packaging machinery
- space-constrained gearboxes
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
- fretting corrosion on a loose shaft seat
- cage damage from operation beyond the limiting speed
Selection pitfalls — read before you substitute
- Codes 00–03 are the exception series: 61801 takes its 12 mm bore from the 10/12/15/17 mm table, so two designations only a few millimetres apart can read alike on paper — order by measured shaft size, not by code arithmetic.
- Only 4.5 mm of radial section separates bore and OD on the 618xx series at 12 mm: ring flex from clamping or an oval housing bore transfers straight into raceway stress, so seat roundness matters more here than on a 6201.
- ZZ shields are non-contact: 61801-ZZ blocks chips and coarse dust but is not waterproof — do not install it expecting a pressure-wash seal, step up to 61801-2RS for that.
- Shielded 61801-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.
- Axial location must clamp the ring face, not the seal area: a shoulder or circlip bearing on the seal side of the 5 mm-wide ring of 61801-ZZ drags the lip and overheats it.
- Assign fits by which ring rotates: an interference shaft fit for a rotating inner ring; if the outer ring rotates instead, reverse the logic — a loose rotating ring creeps and frets its seat.
- SKF spells the shielded version 61801-2Z (one shield: 61801-Z), not "-ZZ": the suffix language differs by brand even though the ISO envelope is identical, so quote the brand designation when ordering.
- The 1.74/0.915 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 61801-ZZ bearing?
A 61801-ZZ deep-groove ball bearing has a 12 mm bore, 21 mm outer diameter and 5 mm width (0.472 × 0.827 × 0.197 in), per ISO 15 boundary dimensions. It is fitted with two non-contact metallic shields.
What internal clearance does 61801-ZZ have?
Unless a clearance suffix says otherwise, 61801-ZZ 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 61801 and verify the residual clearance after mounting.
How should 61801-ZZ be mounted?
Apply the mounting force to the ring being fitted: on a 12 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 61801-ZZ need?
61801-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.
What is the SKF designation and catalogue data for 61801-ZZ?
In the SKF Rolling Bearings catalogue this size is listed as 61801-2Z — two non-contact sheet-metal shields, 12×21×5 mm per ISO 15. Quoted values: C 1.74 kN, C0 0.915 kN, Pu 0.039 kN, limiting speed 36000 r/min, mass 6 g. Brand suffixes (2Z, 2RSH, 2RSL) differ from the industry-neutral spelling 61801-ZZ.
Reviewed & verified by the MPN Base engineering desk against source catalog SKF PUB BU/P1 17000/1 EN (Oct 2018) on 2026-09-24. Read our editorial & correction policy.