61821-2RS bearing: complete specifications & equivalents
The 61821-2RS is a ISO 15 radial bearing sized 105 x 130 x 13 mm (bore x OD x width) with 2RS sealing. Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | SKF |
| Bore diameter d | 105 mm |
| Outer diameter D | 130 mm |
| Width B | 13 mm |
| Material | GCr15 |
| Seal / shield | 2RS |
| Internal clearance | CN / C3 available |
| Tolerance class | P0 |
| Cage | steel, stamped ribbon (J-type) |
| Basic dynamic load rating C | 20.8 kN |
| Basic static load rating C0 | 19.6 kN |
| Fatigue load limit Pu | 1 kN |
| Limiting speed (mechanical) | 2800 rpm |
| Operating temperature | -30 to +110 °C |
| Mass | 330 g |
| Manufacturer designation | SKF 61821-2RS1 |
| 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 | 4.134 in |
|---|---|
| Outer diameter D | 5.118 in |
| Width B | 0.512 in |
| ISO bore code | 21 |
| 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) | 32 of 74 |
| Bore above smallest 61800-series size | 104 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| 61821-2RS-NSK | NSK | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 105×130×13 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting. |
| 61821-NSK | NSK | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 105×130×13 mm envelope per ISO 15; seal variant (2RS vs OPEN) and load ratings differ — confirm sealing and rating before substituting. |
| 61821-RSR-NSK | NSK | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 105×130×13 mm envelope per ISO 15; seal variant (2RS vs RSR) and load ratings differ — confirm sealing and rating before substituting. |
| 61821-ZZ | NSK | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 105×130×13 mm envelope per ISO 15; seal variant (2RS vs ZZ) and load ratings differ — confirm sealing and rating before substituting. |
| 61821-2RS-NTN | NTN | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 105×130×13 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting. |
| 61821-NTN | NTN | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 105×130×13 mm envelope per ISO 15; seal variant (2RS vs OPEN) and load ratings differ — confirm sealing and rating before substituting. |
| 61821-ZZ-NTN | NTN | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 105×130×13 mm envelope per ISO 15; seal variant (2RS 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 61821-2RS model number is decoded
In the 61800-series (diameter series 8 of ISO 15) the last two digits encode the bore: 61821 carries bore code 21 = 105 mm. Outside diameter 130 mm and width 13 mm come from the ISO 15 boundary-dimensions general plan. Suffix -2RS denotes two contact-type elastomer seals over a lifetime grease fill; the sealing lips add drag compared with open or shielded versions. For normal-load mounting with a rotating inner ring on a 105 mm shaft, typical catalogue practice is a m6 shaft seat with an H7 housing bore — verify against the actual load direction and magnitude. SKF's contact-seal catalogue number is 61821-2RS1 (older text: -2RS1), mapped here from the industry-neutral -2RS spelling.
Typical equipment & failure modes
Common applications
- clutch and transmission assemblies
- robotics and automation joints
- lay shafts and idler shafts
- textile machinery
Known failure patterns
- seal-lip hardening and loss of pre-grease in sustained high-temperature service
- grease-life expiry in the sealed-for-life cavity (no relubrication path)
- brinelling from static overload or hammering during mounting
- false brinelling from vibration while the shaft is stationary
Selection pitfalls — read before you substitute
- At 105 mm bore the ring mass is significant: heat 61821 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.
- The 618xx thin section at 105 mm bore has only a 12.5 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 6221.
- Heat is the enemy of the sealed 61821-2RS: sustained running near the lip temperature limit hardens the rubber, after which grease escapes and dirt tracks in — watch the housing temperature in hot drives.
- Never wash a sealed 61821-2RS in solvent or press it home via the outer ring; solvent destroys the grease thickener and mounting force through the seal deforms the lip.
- Never mix components between two 61821-2RS units: rings, cage and balls are factory-matched and are not field-interchangeable, even between identical designations.
- Suffixes stack in a defined order — clearance follows the seal code, e.g. 61821-C3. No clearance suffix means normal CN clearance.
- SKF catalogues the contact-sealed version as 61821-2RS1 (older printings may read -2RS1); it is shipped pre-greased and its 2800 r/min limiting speed is set by seal-lip drag and grease life versus the open bearing's 10000 r/min thermal reference speed.
- The 20.8/19.6 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 61821-2RS bearing?
A 61821-2RS deep-groove ball bearing has a 105 mm bore, 130 mm outer diameter and 13 mm width (4.134 × 5.118 × 0.512 in), per ISO 15 boundary dimensions. It is fitted with two contact rubber seals and is normally pre-greased.
Are 61821 bearings from different brands interchangeable?
For boundary dimensions, yes: every brand's 61821 uses the same ISO 15 envelope (105×130×13 mm). Load ratings, limiting speeds, clearance, precision class and sealing design can differ, so verify those in the supplier catalogue when substituting. Seal suffixes also differ by brand (2RS, DDU, LLU, 2RSL and similar).
What internal clearance does 61821-2RS have?
Unless a clearance suffix says otherwise, 61821-2RS 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 61821 and verify the residual clearance after mounting.
How should 61821-2RS be mounted?
Apply the mounting force to the ring being fitted: on a 105 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 61821-2RS?
In the SKF Rolling Bearings catalogue this size is listed as 61821-2RS1 — two contact elastomer seals over a lifetime grease fill, 105×130×13 mm per ISO 15. Quoted values: C 20.8 kN, C0 19.6 kN, Pu 1 kN, limiting speed 2800 r/min, mass 330 g. Brand suffixes (2Z, 2RSH, 2RSL) differ from the industry-neutral spelling 61821-2RS.
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.