312-ZZ bearing: complete specifications & equivalents
The 312-ZZ is a ISO 15 radial bearing sized 60 x 130 x 31 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 | 60 mm |
| Outer diameter D | 130 mm |
| Width B | 31 mm |
| Material | GCr15 |
| Seal / shield | ZZ |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | steel, stamped ribbon (J-type) |
| Basic dynamic load rating C | 91.3 kN |
| Basic static load rating C0 | 78 kN |
| Fatigue load limit Pu | 3.35 kN |
| Reference speed (thermal) | 9500 rpm |
| Limiting speed (mechanical) | 4800 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 1850 g |
| Manufacturer designation | 312-2Z |
| Standard | ISO 15 |
| Catalog version | SKF PUB BU/P1 17000/1 EN (Oct 2018) |
| Last verified | 2026-09-27 |
Source: catalog reference (SKF PUB BU/P1 17000/1 EN (Oct 2018)) · extracted 2026-09-27
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 & 300-series range
| Bore d | 2.362 in |
|---|---|
| Outer diameter D | 5.118 in |
| Width B | 1.22 in |
| ISO bore code | 12 |
| Radial section height (D−d)/2 | 35 mm |
| Smallest bore in 300-series | 25 mm |
| Largest outer diameter in 300-series | 190 mm |
| Width range across 300-series | 17–43 mm |
| Bore position in 300-series (smallest first) | 8 of 14 |
| Bore above smallest 300-series size | 35 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| 6312-RSR | NSK | partial Main dimensions match; tolerances, seals or internal clearance differ. | NSK bearing NSK 6312VV on the same 60×130×31 mm envelope, but catalogue C/C0 differ (91.3/78 kN vs 90/52 kN) — envelope interchange only after a load check. |
| 6312-M | SKF | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 60×130×31 mm envelope as SKF 6312 M, but catalogue C/C0 differ (91.3/78 kN vs 85.2/52 kN) — envelope match only after a load check. |
| 312 | SKF | full Dimensions and internal design equivalent — standard interchange. | Same 60×130×31 mm envelope and equivalent catalogue ratings; 312 is the open arrangement execution of this size — boundary dimensions interchangeable, only the seal/shield/cage execution differs. |
| 6312 | SKF | partial Main dimensions match; tolerances, seals or internal clearance differ. | SKF SKF 6312 shares the 60×130×31 mm envelope but catalogue C/C0 differ (91.3/78 kN vs 85.2/52 kN) — envelope match, not a load-rating equivalent. |
| 6312-ZZ | SKF | partial Main dimensions match; tolerances, seals or internal clearance differ. | SKF SKF 6312-2Z shares the 60×130×31 mm envelope but catalogue C/C0 differ (91.3/78 kN vs 85.2/52 kN) — envelope match, not a load-rating equivalent. |
| 6312-2RS | SKF | partial Main dimensions match; tolerances, seals or internal clearance differ. | SKF SKF 6312-2RSH shares the 60×130×31 mm envelope but catalogue C/C0 differ (91.3/78 kN vs 85.2/52 kN) — envelope match, not a load-rating equivalent. |
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 312-ZZ model number is decoded
312-2Z is a filling-slot (notched-ring) deep-groove bearing in the legacy 300-series: the last two digits encode the bore: 312 carries code 12 = 60 mm (code × 5). The rings carry loading slots that allow extra balls during assembly, which is what gives the 60×130×31 mm envelope its C 91.3 kN and C0 78 kN ratings (Pu 3.35 kN). SKF spells the double shield 312-2Z (suffix 2Z); the shields are non-contact, retain grease and block coarse debris but are not liquid-tight. Limiting speed 4800 r/min, mass 1850 g. These bearings are built for high purely-radial loads at moderate speeds.
Typical equipment & failure modes
Common applications
- material-handling winches
- slow heavy gearboxes
- farm machinery and harvesters
- construction equipment drives
Known failure patterns
- spalling of the filling-slot edge when balls are hammered through the slot under heavy thrust loading
- dirt entering through the open slot area when external sealing is neglected
- false brinelling from vibration while the shaft stands idle
- fretting corrosion on a creeping shaft or housing seat
Selection pitfalls — read before you substitute
- Shields on 312-ZZ retain grease but do not seal against water; for wet farm duty add external lip seals rather than trusting the shield.
- Limiting speed is just 4800 r/min: filling-slot cages and the slot geometry run cooler below that — overspeed drives cage wear and smearing.
- Filling slots let more balls be packed into the 60×130 mm envelope, which is why 312-ZZ reaches C 91.3 kN — but the slots also mean the two rings separate when the balls align with them, so handle it as a loose-clearance design.
- The slots sit at one angular position: on 312-ZZ, never pass the full radial load across the slot zone during mounting or the ring lip can crack.
- Filling slots let more balls be packed into the 60×130 mm envelope, which is why 312-ZZ reaches C 91.3 kN — but the slots also mean the two rings separate when the balls align with them, so handle it as a loose-clearance design.
- Clearance suffixes follow the seal code in the designation stack (e.g. 312-2Z/C3 in SKF spelling); no suffix means normal CN internal clearance.
Frequently asked questions
What are the dimensions of 312-ZZ?
Filling-slot bearing 312-2Z measures 60×130×31 mm (2.362×5.118×1.22 in), about 1850 g.
What does the designation 312 mean?
It is the legacy 200/300 filling-slot numbering: series 300 and bore code 12 = 60 mm. Filling-slot bearings predate the 6xxx deep-groove spelling.
What fails on 312-ZZ?
Slot-edge chipping under thrust or shock, dirt ingress in the open design and cage wear past the 4800 r/min limiting speed are the typical failure modes.
Is 312-ZZ available sealed?
Shielded executions (-2Z, listed here as 312-ZZ) exist; contact-sealed versions are generally not produced for the filling-slot family.
Reviewed & verified by the MPN Base engineering desk against source catalog SKF PUB BU/P1 17000/1 EN (Oct 2018) on 2026-09-27. Read our editorial & correction policy.