6324-ZZ bearing: complete specifications & equivalents
The 6324-ZZ is a ISO 15 radial bearing sized 120 x 260 x 55 mm (bore x OD x width) with ZZ sealing. Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | SKF |
| Bore diameter d | 120 mm |
| Outer diameter D | 260 mm |
| Width B | 55 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 | 208 kN |
| Basic static load rating C0 | 186 kN |
| Fatigue load limit Pu | 5.7 kN |
| Reference speed (thermal) | 5600 rpm |
| Limiting speed (mechanical) | 2800 rpm |
| Operating temperature | -30 to +120 °C |
| Mass | 12500 g |
| Manufacturer designation | SKF 6324-2Z |
| Standard | ISO 15 |
| Catalog version | SKF PUB BU/P1 17000/1 EN (Oct 2018) |
| Last verified | 2026-09-25 |
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 & 6300-series range
| Bore d | 4.724 in |
|---|---|
| Outer diameter D | 10.236 in |
| Width B | 2.165 in |
| ISO bore code | 24 |
| Radial section height (D−d)/2 | 70 mm |
| Smallest bore in 6300-series | 2 mm |
| Largest outer diameter in 6300-series | 500 mm |
| Width range across 6300-series | 3–95 mm |
| Bore position in 6300-series (smallest first) | 30 of 40 |
| Bore above smallest 6300-series size | 118 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| 6324 | 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 before substituting. |
| 6324-2RS-NSK | NSK | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 120×260×55 mm envelope per ISO 15; seal variant differs (ZZ vs 2RS) — confirm sealing suits the duty. |
| 6324-NSK | NSK | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 120×260×55 mm envelope per ISO 15; seal variant differs (ZZ vs OPEN) — confirm sealing suits the duty. |
| 6324-ZZ-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. |
| 6324-2RS-NTN | NTN | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 120×260×55 mm envelope per ISO 15; seal variant differs (ZZ vs 2RS) — confirm sealing suits the duty. |
| 6324-NTN | NTN | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 120×260×55 mm envelope per ISO 15; seal variant differs (ZZ vs OPEN) — confirm sealing suits the duty. |
| 6324-ZZ-NTN | NTN | 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. |
| 6324-M | SKF | full Dimensions and internal design equivalent — standard interchange. | SKF 6324 M (machined brass cage, open arrangement) is the same-size execution on the 120×260×55 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 6324-ZZ model number is decoded
6324-ZZ carries two non-contact sheet-steel shields that hold the factory grease in and keep coarse debris out; they do not seal against liquids. Within the medium 63xx section (diameter series 3 of ISO 15), multiplying bore code 24 by five gives the 120 mm bore; the 260 mm outside diameter and 55 mm width follow the same boundary-dimension plan. For a rotating inner ring on a 120 mm shaft under normal load, catalogue practice seats it on a m6 shaft fit with an H7 housing bore — confirm against the actual load direction and magnitude before committing. SKF's own suffix is 2Z (this page's industry-neutral spelling is -ZZ); catalogue number 6324-2Z.
Typical equipment & failure modes
Common applications
- heavy conveyors
- pulp and paper machinery
- medium and heavy industrial drives
- large gearboxes
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
- edge loading from shaft deflection or housing misalignment
- rolling-contact fatigue spalling after the rated L10 life is exceeded
Selection pitfalls — read before you substitute
- Mount this 120 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 63xx medium series gains rating at 120 mm bore through a 260 mm OD and 55 mm width; the heavier rolling elements also trade away some speed versus a 6224.
- ZZ shields are non-contact: 6324-ZZ blocks chips and coarse dust but is not waterproof — do not install it expecting a pressure-wash seal, step up to 6324-2RS for that.
- Shielded 6324-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.
- Never mix components between two 6324-ZZ units: rings, cage and balls are factory-matched and are not field-interchangeable, even between identical designations.
- A 120 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 6324-2Z (one shield: 6324-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 6324-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 6324-2Z for high-contamination positions.
- The 208/186 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 6324-ZZ bearing?
A 6324-ZZ deep-groove ball bearing has a 120 mm bore, 260 mm outer diameter and 55 mm width (4.724 × 10.236 × 2.165 in), per ISO 15 boundary dimensions. It is fitted with two non-contact metallic shields.
What does the ZZ suffix on 6324-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 6300 compare with other series at the same 120 mm bore?
The '3' is the medium diameter series: 260×55 mm, 70.0 mm radial section at 120 mm bore, carrying more load than a 6224 but needing a larger housing bore and giving up some speed.
Are 6324 bearings from different brands interchangeable?
For boundary dimensions, yes: every brand's 6324 uses the same ISO 15 envelope (120×260×55 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 is the SKF designation and catalogue data for 6324-ZZ?
In the SKF Rolling Bearings catalogue this size is listed as 6324-2Z — two non-contact sheet-metal shields, 120×260×55 mm per ISO 15. Quoted values: C 208 kN, C0 186 kN, Pu 5.7 kN, limiting speed 2800 r/min, mass 12500 g. Brand suffixes (2Z, 2RSH, 2RSL) differ from the industry-neutral spelling 6324-ZZ.
Reviewed & verified by the MPN Base engineering desk against source catalog SKF PUB BU/P1 17000/1 EN (Oct 2018) on 2026-09-25. Read our editorial & correction policy.