6221-2RS bearing: complete specifications & equivalents
The 6221-2RS is a ISO 15 radial bearing sized 105 x 190 x 36 mm (bore x OD x width) with 2RS sealing. Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Bore diameter d | 105 mm |
| Outer diameter D | 190 mm |
| Width B | 36 mm |
| Seal / shield | 2RS |
| Internal clearance | CN / C3 available |
| Tolerance class | P0 |
| Cage | steel, stamped ribbon (J-type) |
| Operating temperature | -30 to +110 °C |
| Mass (geometry estimate) | 3618 g |
| Standard | ISO 15 |
| Catalog version | iso15-ed4-geometry |
| Last verified | 2026-09-23 |
Source: ISO 15 boundary-dimensions standard · extracted 2026-09-23
Standard-interchange bearing: dimensions per ISO 15; CN clearance, P0 tolerance and a stamped-steel cage are catalogue defaults unless the supplier states otherwise, and mass is a geometry-derived estimate. Brand catalogue load ratings and limiting speeds for 6221 are being backfilled — use the inquiry form for certified values.
Dimensions in inches & 6200-series range
| Bore d | 4.134 in |
|---|---|
| Outer diameter D | 7.48 in |
| Width B | 1.417 in |
| ISO bore code | 21 |
| Radial section height (D−d)/2 | 42.5 mm |
| Smallest bore in 6200-series | 10 mm |
| Largest outer diameter in 6200-series | 400 mm |
| Width range across 6200-series | 9–65 mm |
| Bore position in 6200-series (smallest first) | 22 of 33 |
| Bore above smallest 6200-series size | 95 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| 6221 | SKF | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 105×190×36 mm envelope per ISO 15; seal variant differs (2RS vs OPEN) — confirm sealing suits the duty. |
| 6221-ZZ | SKF | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 105×190×36 mm envelope per ISO 15; seal variant differs (2RS 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 6221-2RS model number is decoded
In the 6200-series (ISO 15 diameter series 2) the last two digits encode the bore: 6221 carries bore code 21 = 105 mm. Outside diameter 190 mm and width 36 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.
Typical equipment & failure modes
Common applications
- pulp and paper machinery
- medium and heavy industrial drives
- large gearboxes
- industrial fans and blowers
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)
- 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 105 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 62xx light series is the default general-purpose section at 105 mm bore; before upgrading to a 6321 for extra capacity, confirm the housing accepts a 190 mm OD and 36 mm width — it is not a drop-in swap.
- Contact seals add drag and heat: 6221-2RS runs slower and cooler-limited than the open 6221; rubber lips are generally limited to roughly 80–110 °C continuous depending on grease, and C3 clearance is the common hot-duty choice.
- Never wash a sealed 6221-2RS in solvent or press it home via the outer ring; solvent destroys the grease thickener and mounting force through the seal deforms the lip.
- Deep-groove ball bearings tolerate only minutes of misalignment; if the 190 mm housing cannot be aligned, switch to a self-aligning type rather than shimming 6221-2RS.
Frequently asked questions
What are the dimensions of a 6221-2RS bearing?
A 6221-2RS deep-groove ball bearing has a 105 mm bore, 190 mm outer diameter and 36 mm width (4.134 × 7.48 × 1.417 in), per ISO 15 boundary dimensions. It is fitted with two contact rubber seals and is normally pre-greased. Geometry-based estimated mass is about 3618 g for a steel-cage unit; catalogue masses vary slightly with seal and cage design.
How does the 6221 bore code work?
The last two digits of 6221 are bore code 21, giving 21 × 5 = 105 mm bore. The 190 mm outside diameter and 36 mm width follow the ISO 15 diameter series, not the bore code alone.
What does the 2RS suffix on 6221-2RS mean?
2RS means two contact elastomer seals, one each side, usually over a lifetime grease fill. Sealing against dust and moisture is better than ZZ shields, but the lip drag lowers the speed and temperature ceiling.
How does the 6200 compare with other series at the same 105 mm bore?
The '2' is the light diameter series: 190×36 mm with a 42.5 mm radial section at 105 mm bore. A 6321 on the same bore is larger and higher-rated; a 6021 is smaller and lower-rated.
Are 6221 bearings from different brands interchangeable?
For boundary dimensions, yes: every brand's 6221 uses the same ISO 15 envelope (105×190×36 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 and similar).
Reviewed & verified by the MPN Base engineering desk against source catalog iso15-ed4-geometry on 2026-09-23. Read our editorial & correction policy.