61820 bearing: complete specifications & equivalents
The 61820 is a ISO 15 radial bearing sized 100 x 125 x 13 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | SKF |
| Bore diameter d | 100 mm |
| Outer diameter D | 125 mm |
| Width B | 13 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 | 17.8 kN |
| Basic static load rating C0 | 18.3 kN |
| Fatigue load limit Pu | 0.95 kN |
| Reference speed (thermal) | 10000 rpm |
| Limiting speed (mechanical) | 6300 rpm |
| Operating temperature | -40 to +150 °C |
| Mass | 300 g |
| Manufacturer designation | SKF 61820 |
| 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 | 3.937 in |
|---|---|
| Outer diameter D | 4.921 in |
| Width B | 0.512 in |
| ISO bore code | 20 |
| Radial section height (D−d)/2 | 12.5 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) | 31 of 74 |
| Bore above smallest 61800-series size | 99 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| 61820-2RS-NSK | NSK | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 100×125×13 mm envelope per ISO 15; seal variant (OPEN vs 2RS) and load ratings differ — confirm sealing and rating before substituting. |
| 61820-NSK | NSK | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 100×125×13 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting. |
| 61820-RSR-NSK | NSK | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 100×125×13 mm envelope per ISO 15; seal variant (OPEN vs RSR) and load ratings differ — confirm sealing and rating before substituting. |
| 61820-ZZ | NSK | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 100×125×13 mm envelope per ISO 15; seal variant (OPEN vs ZZ) and load ratings differ — confirm sealing and rating before substituting. |
| 61820-2RS-NTN | NTN | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 100×125×13 mm envelope per ISO 15; seal variant (OPEN vs 2RS) and load ratings differ — confirm sealing and rating before substituting. |
| 61820-NTN | NTN | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 100×125×13 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting. |
| 61820-RSR-NTN | NTN | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 100×125×13 mm envelope per ISO 15; seal variant (OPEN vs RSR) and load ratings differ — confirm sealing and rating before substituting. |
| 61820-ZZ-NTN | NTN | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 100×125×13 mm envelope per ISO 15; seal variant (OPEN vs ZZ) and load ratings differ — confirm sealing and rating 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 61820 model number is decoded
In the 61800-series (diameter series 8 of ISO 15) the last two digits encode the bore: 61820 carries bore code 20 = 100 mm. Outside diameter 125 mm and width 13 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 100 mm shaft, typical catalogue practice is a k5 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
- 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
- false brinelling from vibration while the shaft is stationary
- fretting corrosion on a loose shaft seat
Selection pitfalls — read before you substitute
- At 100 mm bore the ring mass is significant: heat 61820 on an induction heater (max 120 °C), never over an open flame, and plan puller access or a withdrawal sleeve now for the day it has to come off again.
- Only 12.5 mm of radial section separates bore and OD on the 618xx series at 100 mm: ring flex from clamping or an oval housing bore transfers straight into raceway stress, so seat roundness matters more here than on a 6220.
- Storage matters for open bearings: 61820 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.
- 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 61820 units.
- Deep-groove ball bearings tolerate only minutes of misalignment; if the 125 mm housing cannot be aligned, switch to a self-aligning type rather than shimming 61820.
- 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.
- The open 61820 needs external sealing and application-supplied lubrication; in the SKF catalogue the protected variants are separate order numbers 61820-2Z (shields) and 61820-2RSH (contact seals), not suffix-free 61820.
- The 17.8/18.3 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 61820 bearing?
A 61820 deep-groove ball bearing has a 100 mm bore, 125 mm outer diameter and 13 mm width (3.937 × 4.921 × 0.512 in), per ISO 15 boundary dimensions. It is an open bearing with no seals or shields.
Are 61820 bearings from different brands interchangeable?
For boundary dimensions, yes: every brand's 61820 uses the same ISO 15 envelope (100×125×13 mm). Load ratings, limiting speeds, clearance, precision class and sealing design can differ, so verify those in the supplier catalogue when substituting.
What internal clearance does 61820 have?
Unless a clearance suffix says otherwise, 61820 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 61820 and verify the residual clearance after mounting.
How should 61820 be mounted?
Apply the mounting force to the ring being fitted: on a 100 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 is the SKF designation and catalogue data for 61820?
In the SKF Rolling Bearings catalogue this size is listed as 61820 — the open (unsealed) execution, 100×125×13 mm per ISO 15. Quoted values: C 17.8 kN, C0 18.3 kN, Pu 0.95 kN, limiting speed 6300 r/min, mass 300 g. Brand suffixes (2Z, 2RSH, 2RSL) differ from the industry-neutral spelling 61820.
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.