61840 bearing: complete specifications & equivalents
The 61840 is a ISO 15 radial bearing sized 200 x 250 x 24 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Bore diameter d | 200 mm |
| Outer diameter D | 250 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 | 76.1 kN |
| Basic static load rating C0 | 102 kN |
| Fatigue load limit Pu | 2.9 kN |
| Reference speed (thermal) | 5000 rpm |
| Limiting speed (mechanical) | 3200 rpm |
| Operating temperature | -40 to +150 °C |
| Mass | 2350 g |
| Manufacturer designation | SKF 61840 |
| 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 | 7.874 in |
|---|---|
| Outer diameter D | 9.843 in |
| Width B | 0.945 in |
| ISO bore code | 40 |
| Radial section height (D−d)/2 | 25 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) | 32 of 39 |
| Bore above smallest 61800-series size | 190 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| 61840 | 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 61840 model number is decoded
In the 61800-series (ISO 15 diameter series 8) the last two digits encode the bore: 61840 carries bore code 40 = 200 mm. Outside diameter 250 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 200 mm shaft, typical catalogue practice is a m6 shaft seat with an H7 housing bore — verify against the actual load direction and magnitude.
Typical equipment & failure modes
Common applications
- space-constrained gearboxes
- clutch and transmission assemblies
- robotics and automation joints
- lay shafts and idler shafts
Known failure patterns
- contamination wear from dust and dirt ingress through the open arrangement
- lubricant starvation when no regreasing interval is maintained
- cage damage from operation beyond the limiting speed
- electrical pitting in VFD-driven motors without grounding protection
Selection pitfalls — read before you substitute
- Mount this 200 mm bore bearing by heating the inner ring (induction heater, max 120 °C) — never drive it home through the outer ring or balls, that brinells the raceways.
- The 618xx thin section at 200 mm bore has only a 25.0 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 6240.
- The open 61840 has no lubricant retention: grease escapes and contaminants migrate straight into the 200×250×24 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 61840 units.
- Deep-groove ball bearings tolerate only minutes of misalignment; if the 250 mm housing cannot be aligned, switch to a self-aligning type rather than shimming 61840.
- The open 61840 needs external sealing and application-supplied lubrication; in the SKF catalogue the protected variants are separate order numbers 61840-2Z (shields) and 61840-2RSH (contact seals), not suffix-free 61840.
- The 76.1/102 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 61840 bearing?
A 61840 deep-groove ball bearing has a 200 mm bore, 250 mm outer diameter and 24 mm width (7.874 × 9.843 × 0.945 in), per ISO 15 boundary dimensions. It is an open bearing with no seals or shields.
How does the 61840 bore code work?
The last two digits of 61840 are bore code 40, giving 40 × 5 = 200 mm bore. The 250 mm outside diameter and 24 mm width follow the ISO 15 diameter series, not the bore code alone.
What does no suffix on 61840 mean?
A bare 61840 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 200 mm bore?
618 is an extra-thin section: 250×24 mm, only 25.0 mm radial section at 200 mm bore, far smaller than a 6240, for space-limited layouts at the cost of load rating and misalignment tolerance.
What is the SKF designation and catalogue data for 61840?
In the SKF Rolling Bearings catalogue this size is listed as 61840 — the open (unsealed) execution, 200×250×24 mm per ISO 15. Quoted values: C 76.1 kN, C0 102 kN, Pu 2.9 kN, limiting speed 3200 r/min, mass 2350 g. Brand suffixes (2Z, 2RSH, 2RSL) differ from the industry-neutral spelling 61840.
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.