6021 bearing: complete specifications & equivalents
The 6021 is a ISO 15 radial bearing sized 105 x 160 x 26 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | SKF |
| Bore diameter d | 105 mm |
| Outer diameter D | 160 mm |
| Width B | 26 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 | 65.5 kN |
| Fatigue load limit Pu | 2.4 kN |
| Reference speed (thermal) | 8500 rpm |
| Limiting speed (mechanical) | 5300 rpm |
| Operating temperature | -40 to +150 °C |
| Mass | 1600 g |
| Manufacturer designation | SKF 6021 |
| 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 & 6000-series range
| Bore d | 4.134 in |
|---|---|
| Outer diameter D | 6.299 in |
| Width B | 1.024 in |
| ISO bore code | 21 |
| Radial section height (D−d)/2 | 27.5 mm |
| Smallest bore in 6000-series | 4 mm |
| Largest outer diameter in 6000-series | 1150 mm |
| Width range across 6000-series | 4–155 mm |
| Bore position in 6000-series (smallest first) | 28 of 61 |
| Bore above smallest 6000-series size | 101 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| 6021 | ISO 15 | full Dimensions and internal design equivalent — standard interchange. | ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier. |
| 6021-2RS-NSK | NSK | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 105×160×26 mm envelope per ISO 15; seal variant differs (OPEN vs 2RS) — confirm sealing suits the duty. |
| 6021-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. |
| 6021-RSR | NSK | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 105×160×26 mm envelope per ISO 15; seal variant differs (OPEN vs RSR) — confirm sealing suits the duty. |
| 6021-ZZ-NSK | NSK | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 105×160×26 mm envelope per ISO 15; seal variant differs (OPEN vs ZZ) — confirm sealing suits the duty. |
| 6021-M | SKF | full Dimensions and internal design equivalent — standard interchange. | SKF 6021 M (machined brass cage, open arrangement) is the same-size execution on the 105×160×26 mm envelope with ratings within 10 % — boundary dimensions interchangeable. |
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 6021 model number is decoded
In the 6000-series (diameter series 0 of ISO 15) the last two digits encode the bore: 6021 carries bore code 21 = 105 mm. Outside diameter 160 mm and width 26 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 105 mm shaft, typical catalogue practice is a m6 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
- hoists and winches
- heavy conveyors
- pulp and paper machinery
- medium and heavy industrial drives
Known failure patterns
- contamination wear from dust and dirt ingress through the open arrangement
- lubricant starvation when no regreasing interval is maintained
- raceway smearing under marginal lubrication at start-up
- edge loading from shaft deflection or housing misalignment
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.
- Choosing the 60xx extra-light section saves radial space at 105 mm bore, but the trade-off is rating: if the drive sees shock or frequent start-stop cycles, re-check the L10 life against a 6221 before committing to the smaller envelope.
- The open 6021 has no lubricant retention: grease escapes and contaminants migrate straight into the 105×160×26 mm raceway, so specify a sealed arrangement for dusty or washdown duty.
- Open bearings tolerate the highest speeds in the 6000-series but need a defined regreasing interval; run-to-failure lubrication is the dominant cause of early failure in open 6021 units.
- A 105 mm bore listing showing the right d/D/B but no standard or precision-class reference may be a loose-tolerance import; measure bore/OD spread before fitting it to a machined shaft.
- 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 6021 needs external sealing and application-supplied lubrication; in the SKF catalogue the protected variants are separate order numbers 6021-2Z (shields) and 6021-2RSH (contact seals), not suffix-free 6021.
- The 76.1/65.5 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 6021 bearing?
A 6021 deep-groove ball bearing has a 105 mm bore, 160 mm outer diameter and 26 mm width (4.134 × 6.299 × 1.024 in), per ISO 15 boundary dimensions. It is an open bearing with no seals or shields.
How does the 6021 bore code work?
The last two digits of 6021 are bore code 21, giving 21 × 5 = 105 mm bore. The 160 mm outside diameter and 26 mm width follow the ISO 15 diameter series, not the bore code alone.
What does no suffix on 6021 mean?
A bare 6021 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 6000 compare with other series at the same 105 mm bore?
The second digit is the diameter series: 60 is the smallest standard section (160×26 mm, 27.5 mm radial section) at 105 mm bore — below 62/63/64 in load capacity, for light loads in compact spaces.
What is the SKF designation and catalogue data for 6021?
In the SKF Rolling Bearings catalogue this size is listed as 6021 — the open (unsealed) execution, 105×160×26 mm per ISO 15. Quoted values: C 76.1 kN, C0 65.5 kN, Pu 2.4 kN, limiting speed 5300 r/min, mass 1600 g. Brand suffixes (2Z, 2RSH, 2RSL) differ from the industry-neutral spelling 6021.
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.