61801 bearing: complete specifications & equivalents
The 61801 is a ISO 15 radial bearing sized 12 x 21 x 5 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Bore diameter d | 12 mm |
| Outer diameter D | 21 mm |
| Width B | 5 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 | 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) | 43000 rpm |
| Operating temperature | -40 to +150 °C |
| Mass | 6 g |
| Manufacturer designation | SKF 61801 |
| 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 | 10 mm |
| Largest outer diameter in 61800-series | 420 mm |
| Width range across 61800-series | 5–38 mm |
| Bore position in 61800-series (smallest first) | 2 of 39 |
| Bore above smallest 61800-series size | 2 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| 61801 | ISO 15 | full Dimensions and internal design equivalent — standard interchange. | ISO 15 boundary-dimension envelope; brand-specific OEM equivalents (NSK/FAG/NTN) pending multi-source data. |
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 model number is decoded
In the 61800-series (ISO 15 diameter series 8) the last two digits encode the bore: 61801 carries bore code 01 = 12 mm. Codes 00–03 follow the 10/12/15/17 mm exception table rather than code × 5. Outside diameter 21 mm and width 5 mm come from the ISO 15 boundary-dimensions general plan. With no seal suffix the bearing is open: no shields or seals are fitted and lubrication is supplied by the application. For normal-load mounting with a rotating inner ring on a 12 mm shaft, typical catalogue practice is a j5 shaft seat with an H7 housing bore — verify against the actual load direction and magnitude.
Typical equipment & failure modes
Common applications
- lay shafts and idler shafts
- textile machinery
- packaging machinery
- space-constrained gearboxes
Known failure patterns
- contamination wear from dust and dirt ingress through the open arrangement
- lubricant starvation when no regreasing interval is maintained
- electrical pitting in VFD-driven motors without grounding protection
- raceway smearing under marginal lubrication at start-up
Selection pitfalls — read before you substitute
- Bore codes 00–03 use the exception table: 61801 fits a 12 mm shaft — the code × 5 mnemonic does not apply below code 04 (it would imply 0 mm for code 00).
- The 618xx thin section at 12 mm bore has only a 4.5 mm radial section height: it saves space but is highly sensitive to misalignment, shaft deflection and shock loads — verify shaft stiffness before choosing it over a 6201.
- The open 61801 has no lubricant retention: grease escapes and contaminants migrate straight into the 12×21×5 mm raceway, so specify a sealed arrangement for dusty or washdown duty.
- Open bearings tolerate the highest speeds in the 61800-series but need a defined regreasing interval; run-to-failure lubrication is the dominant cause of early failure in open 61801 units.
- A 12 mm bore listing showing the right d/D/B but no standard or precision-class reference may be a loose-tolerance import; measure bore/OD spread before fitting it to a machined shaft.
- The open 61801 needs external sealing and application-supplied lubrication; in the SKF catalogue the protected variants are separate order numbers 61801-2Z (shields) and 61801-2RSH (contact seals), not suffix-free 61801.
- 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 bearing?
A 61801 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 an open bearing with no seals or shields.
Why does 61801 not follow the bore-code × 5 rule?
Codes 00–03 use the exception table (10, 12, 15 and 17 mm): 61801 with code 01 has a 12 mm bore. The code × 5 convention starts at code 04 (20 mm).
What does no suffix on 61801 mean?
A bare 61801 designation means open: no shields or seals, normal CN radial clearance and P0 normal tolerance unless further suffixes are ordered. The application must supply and retain the lubrication.
How does the 61800 compare with other series at the same 12 mm bore?
618 is an extra-thin section: 21×5 mm, only 4.5 mm radial section at 12 mm bore, far smaller than a 6201, for space-limited layouts at the cost of load rating and misalignment tolerance.
What is the SKF designation and catalogue data for 61801?
In the SKF Rolling Bearings catalogue this size is listed as 61801 — the open (unsealed) execution, 12×21×5 mm per ISO 15. Quoted values: C 1.74 kN, C0 0.915 kN, Pu 0.039 kN, limiting speed 43000 r/min, mass 6 g. Brand suffixes (2Z, 2RSH, 2RSL) differ from the industry-neutral spelling 61801.
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.