61844 bearing: complete specifications & equivalents
The 61844 is a ISO 15 radial bearing sized 220 x 270 x 24 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | SKF |
| Bore diameter d | 220 mm |
| Outer diameter D | 270 mm |
| Width B | 24 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 | 78 kN |
| Basic static load rating C0 | 110 kN |
| Fatigue load limit Pu | 3 kN |
| Reference speed (thermal) | 4500 rpm |
| Limiting speed (mechanical) | 2800 rpm |
| Operating temperature | -40 to +150 °C |
| Mass | 2550 g |
| Manufacturer designation | SKF 61844 |
| 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 | 8.661 in |
|---|---|
| Outer diameter D | 10.63 in |
| Width B | 0.945 in |
| ISO bore code | 44 |
| Radial section height (D−d)/2 | 25 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) | 43 of 74 |
| Bore above smallest 61800-series size | 219 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| 61844-FAG | FAG | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 220×270×24 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting. |
| 61844 | ISO 15 | full Dimensions and internal design equivalent — standard interchange. | ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier. |
| 61844-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. |
| 61844-ZZ | NSK | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 220×270×24 mm envelope per ISO 15; seal variant differs (OPEN vs ZZ) — confirm sealing suits the duty. |
| 61844-NTN | NTN | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 220×270×24 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting. |
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 61844 model number is decoded
In the 61800-series (diameter series 8 of ISO 15) the last two digits encode the bore: 61844 carries bore code 44 = 220 mm. Outside diameter 270 mm and width 24 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 220 mm shaft, typical catalogue practice is a m6 shaft seat with an H7 housing bore — verify against the actual load direction and magnitude. 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
- packaging machinery
- space-constrained gearboxes
- clutch and transmission assemblies
- robotics and automation joints
Known failure patterns
- contamination wear from dust and dirt ingress through the open arrangement
- lubricant starvation when no regreasing interval is maintained
- fretting corrosion on a loose shaft seat
- cage damage from operation beyond the limiting speed
Selection pitfalls — read before you substitute
- Large bores like the 220 mm of 61844 demand clean, burr-free seats; one raised burr under a ring this size cocks the bearing and concentrates load at the raceway edge, cutting life drastically.
- Only 25.0 mm of radial section separates bore and OD on the 618xx series at 220 mm: ring flex from clamping or an oval housing bore transfers straight into raceway stress, so seat roundness matters more here than on a 6244.
- The open 61844 has no lubricant retention: grease escapes and contaminants migrate straight into the 220×270×24 mm raceway, so specify a sealed arrangement for dusty or washdown duty.
- Storage matters for open bearings: 61844 leaves the factory with rust preventive only, so clean it and apply the service grease at assembly even if the rings look oily from the wrapper.
- Axial location must clamp the ring face, not the seal area: a shoulder or circlip bearing on the seal side of the 24 mm-wide ring of 61844 drags the lip and overheats it.
- Measure the shaft, do not trust the drawing: a 220 mm nominal journal worn by even 0.02 mm turns an interference seat into a creeping fit that frets the bore of 61844.
- The open 61844 needs external sealing and application-supplied lubrication; in the SKF catalogue the protected variants are separate order numbers 61844-2Z (shields) and 61844-2RSH (contact seals), not suffix-free 61844.
- The 78/110 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 61844 bearing?
A 61844 deep-groove ball bearing has a 220 mm bore, 270 mm outer diameter and 24 mm width (8.661 × 10.63 × 0.945 in), per ISO 15 boundary dimensions. It is an open bearing with no seals or shields.
How should 61844 be mounted?
Apply the mounting force to the ring being fitted: on a 220 mm shaft seat the press load must pass through the inner-ring face only. Induction heating of the inner ring (max 120 °C) is the clean method at this size. Never strike the outer ring, the cage or the seals.
What lubrication does 61844 need?
The open 61844 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.
How does the 61844 bore code work?
The last two digits of 61844 are bore code 44, giving 44 × 5 = 220 mm bore. The 270 mm outside diameter and 24 mm width follow the ISO 15 diameter series, not the bore code alone.
What is the SKF designation and catalogue data for 61844?
In the SKF Rolling Bearings catalogue this size is listed as 61844 — the open (unsealed) execution, 220×270×24 mm per ISO 15. Quoted values: C 78 kN, C0 110 kN, Pu 3 kN, limiting speed 2800 r/min, mass 2550 g. Brand suffixes (2Z, 2RSH, 2RSL) differ from the industry-neutral spelling 61844.
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.