6021-ZZ bearing: complete specifications & equivalents
The 6021-ZZ is a ISO 15 radial bearing sized 105 x 160 x 26 mm (bore x OD x width) with ZZ sealing. Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Bore diameter d | 105 mm |
| Outer diameter D | 160 mm |
| Width B | 26 mm |
| Material | GCr15 |
| Seal / shield | ZZ |
| 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) | 4300 rpm |
| Operating temperature | -30 to +120 °C |
| Mass | 1650 g |
| Manufacturer designation | SKF 6021-2Z |
| 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 | 10 mm |
| Largest outer diameter in 6000-series | 420 mm |
| Width range across 6000-series | 8–65 mm |
| Bore position in 6000-series (smallest first) | 22 of 35 |
| Bore above smallest 6000-series size | 95 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| 6021 | ISO 15 | verify Commonly quoted cross reference; confirm against the target catalog before ordering. | ISO 15 boundary-dimension envelope; seal suffix convention varies by brand (2RS / DDU / LLU / 2RSR) — verify seal design and temperature range. Brand-specific OEM equivalents pending multi-source data. |
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-ZZ model number is decoded
In the 6000-series (ISO 15 diameter series 0) 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. Suffix -ZZ denotes two non-contact metallic shields; they retain grease and block coarse debris but are not liquid-tight. 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
- hoists and winches
- heavy conveyors
- pulp and paper machinery
- medium and heavy industrial drives
Known failure patterns
- fine-particle abrasion when non-contact shields let dust past in dirty duty
- grease aging in the shield-for-life cavity with no relubrication path
- rolling-contact fatigue spalling after the rated L10 life is exceeded
- brinelling from static overload or hammering during mounting
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 60xx extra-light section at 105 mm bore uses a smaller 160 mm OD than a 6221; load ratings are lower, so do not replace a failed 62-series bearing with a 60-series without re-rating the load.
- ZZ shields are non-contact: 6021-ZZ blocks chips and coarse dust but is not waterproof — do not install it expecting a pressure-wash seal, step up to 6021-2RS for that.
- Shielded 6021-ZZ units are typically greased for life; prying the shields out for regreasing usually bends them and leaves a gap that throws grease in service.
- 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.
- SKF spells the shielded version 6021-2Z (one shield: 6021-Z), not "-ZZ": the suffix language differs by brand even though the ISO envelope is identical, so quote the brand designation when ordering.
- The single-shield execution 6021-Z is a distinct order number in catalogue 17000: it suits open gears or oil-bath arrangements where the unshielded face faces the lubricant, and it is not interchangeable with the double-shield 6021-2Z for high-contamination positions.
- 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-ZZ bearing?
A 6021-ZZ 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 fitted with two non-contact metallic 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 the ZZ suffix on 6021-ZZ mean?
ZZ means two non-contact sheet-metal shields, one each side. They retain factory grease and block coarse particles with little friction, but do not seal against liquids, fine dust or pressure washing.
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-ZZ?
In the SKF Rolling Bearings catalogue this size is listed as 6021-2Z — two non-contact sheet-metal shields, 105×160×26 mm per ISO 15. Quoted values: C 76.1 kN, C0 65.5 kN, Pu 2.4 kN, limiting speed 4300 r/min, mass 1650 g. Brand suffixes (2Z, 2RSH, 2RSL) differ from the industry-neutral spelling 6021-ZZ.
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.