61811 bearing: complete specifications & equivalents
The 61811 is a ISO 15 radial bearing sized 55 x 72 x 9 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | SKF |
| Bore diameter d | 55 mm |
| Outer diameter D | 72 mm |
| Width B | 9 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 | 9.04 kN |
| Basic static load rating C0 | 8.8 kN |
| Fatigue load limit Pu | 0.375 kN |
| Reference speed (thermal) | 19000 rpm |
| Limiting speed (mechanical) | 12000 rpm |
| Operating temperature | -40 to +150 °C |
| Mass | 83 g |
| Manufacturer designation | SKF 61811 |
| 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 & 61800-series range
| Bore d | 2.165 in |
|---|---|
| Outer diameter D | 2.835 in |
| Width B | 0.354 in |
| ISO bore code | 11 |
| Radial section height (D−d)/2 | 8.5 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) | 22 of 74 |
| Bore above smallest 61800-series size | 54 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| 61811-2RS-NSK | NSK | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 55×72×9 mm envelope per ISO 15; seal variant differs (OPEN vs 2RS) — confirm sealing suits the duty. |
| 61811-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. |
| 61811-RSR-NSK | NSK | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 55×72×9 mm envelope per ISO 15; seal variant differs (OPEN vs RSR) — confirm sealing suits the duty. |
| 61811-ZZ | NSK | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 55×72×9 mm envelope per ISO 15; seal variant differs (OPEN vs ZZ) — confirm sealing suits the duty. |
| 61811-2RS-NTN | NTN | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 55×72×9 mm envelope per ISO 15; seal variant differs (OPEN vs 2RS) — confirm sealing suits the duty. |
| 61811-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. |
| 61811-RSR-NTN | NTN | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 55×72×9 mm envelope per ISO 15; seal variant differs (OPEN vs RSR) — confirm sealing suits the duty. |
| 61811-ZZ-NTN | NTN | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 55×72×9 mm envelope per ISO 15; seal variant differs (OPEN vs ZZ) — confirm sealing suits the duty. |
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 61811 model number is decoded
61811 is supplied open, without shields or seals, so the arrangement around it must supply and retain the lubricant. Within the extra-thin 618xx section (diameter series 8 of ISO 15), multiplying bore code 11 by five gives the 55 mm bore; the 72 mm outside diameter and 9 mm width follow the same boundary-dimension plan. For a rotating inner ring on a 55 mm shaft under normal load, catalogue practice seats it on a k5 shaft fit with an H7 housing bore — confirm against the actual load direction and magnitude before committing. 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
- robotics and automation joints
- lay shafts and idler shafts
- textile machinery
- packaging machinery
Known failure patterns
- contamination wear from dust and dirt ingress through the open arrangement
- lubricant starvation when no regreasing interval is maintained
- edge loading from shaft deflection or housing misalignment
- rolling-contact fatigue spalling after the rated L10 life is exceeded
Selection pitfalls — read before you substitute
- Interference on a 55 mm shaft plus running heat consumes radial clearance: where the shaft runs hot or the fit is tight, order 61811 with C3 clearance and re-check the residual value after mounting.
- The 618xx thin section at 55 mm bore has only a 8.5 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 6211.
- The open 61811 has no lubricant retention: grease escapes and contaminants migrate straight into the 55×72×9 mm raceway, so specify a sealed arrangement for dusty or washdown duty.
- Storage matters for open bearings: 61811 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.
- The housing bore for the 72 mm OD should be round within IT7; an oval bore pinches the outer ring of 61811 and shows up later as two-point loaded raceway wear.
- Suffixes stack in a defined order — clearance follows the seal code, e.g. 61811-C3. No clearance suffix means normal CN clearance.
- The open 61811 needs external sealing and application-supplied lubrication; in the SKF catalogue the protected variants are separate order numbers 61811-2Z (shields) and 61811-2RSH (contact seals), not suffix-free 61811.
- The 9.04/8.8 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 61811 bearing?
A 61811 deep-groove ball bearing has a 55 mm bore, 72 mm outer diameter and 9 mm width (2.165 × 2.835 × 0.354 in), per ISO 15 boundary dimensions. It is an open bearing with no seals or shields.
What internal clearance does 61811 have?
Unless a clearance suffix says otherwise, 61811 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 61811 and verify the residual clearance after mounting.
How should 61811 be mounted?
Apply the mounting force to the ring being fitted: on a 55 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 61811 need?
The open 61811 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.
What is the SKF designation and catalogue data for 61811?
In the SKF Rolling Bearings catalogue this size is listed as 61811 — the open (unsealed) execution, 55×72×9 mm per ISO 15. Quoted values: C 9.04 kN, C0 8.8 kN, Pu 0.375 kN, limiting speed 12000 r/min, mass 83 g. Brand suffixes (2Z, 2RSH, 2RSL) differ from the industry-neutral spelling 61811.
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.