307-ZZ bearing: complete specifications & equivalents
The 307-ZZ is a ISO 15 radial bearing sized 35 x 80 x 21 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 | 35 mm |
| Outer diameter D | 80 mm |
| Width B | 21 mm |
| Material | GCr15 |
| Seal / shield | ZZ |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | steel, stamped ribbon (J-type) |
| Basic dynamic load rating C | 34.7 kN |
| Basic static load rating C0 | 26.5 kN |
| Fatigue load limit Pu | 1.12 kN |
| Reference speed (thermal) | 16000 rpm |
| Limiting speed (mechanical) | 7600 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 480 g |
| Manufacturer designation | 307-2Z |
| 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 | 1.378 in |
|---|---|
| Outer diameter D | 3.15 in |
| Width B | 0.827 in |
| ISO bore code | 07 |
| Radial section height (D−d)/2 | 22.5 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) | 3 of 14 |
| Bore above smallest 300-series size | 10 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| 6307-RSR | NSK | partial Main dimensions match; tolerances, seals or internal clearance differ. | NSK bearing NSK 6307VV on the same 35×80×21 mm envelope, but catalogue C/C0 differ (34.7/26.5 kN vs 36.5/19.2 kN) — envelope interchange only after a load check. |
| 6307-M | SKF | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 35×80×21 mm envelope as SKF 6307 M, but catalogue C/C0 differ (34.7/26.5 kN vs 35.1/19 kN) — envelope match only after a load check. |
| W6307-2RS | SKF | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 35×80×21 mm envelope, but the stainless and chrome-steel executions carry different catalogue ratings (34.7/26.5 kN vs 28.6/19 kN) — envelope match, not a load-rating equivalent; choose by corrosion versus load duty. |
| 307 | SKF | full Dimensions and internal design equivalent — standard interchange. | Same 35×80×21 mm envelope and equivalent catalogue ratings; 307 is the open arrangement execution of this size — boundary dimensions interchangeable, only the seal/shield/cage execution differs. |
| 6307 | SKF | partial Main dimensions match; tolerances, seals or internal clearance differ. | SKF SKF 6307 shares the 35×80×21 mm envelope but catalogue C/C0 differ (34.7/26.5 kN vs 35.1/19 kN) — envelope match, not a load-rating equivalent. |
| 6307-ZZ | SKF | partial Main dimensions match; tolerances, seals or internal clearance differ. | SKF SKF 6307-2Z shares the 35×80×21 mm envelope but catalogue C/C0 differ (34.7/26.5 kN vs 35.1/19 kN) — envelope match, not a load-rating equivalent. |
| 6307-2RS | SKF | partial Main dimensions match; tolerances, seals or internal clearance differ. | SKF SKF 6307-2RSH shares the 35×80×21 mm envelope but catalogue C/C0 differ (34.7/26.5 kN vs 35.1/19 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 307-ZZ model number is decoded
307-2Z is a filling-slot (notched-ring) deep-groove bearing in the legacy 300-series: the last two digits encode the bore: 307 carries code 07 = 35 mm (code × 5). The rings carry loading slots that allow extra balls during assembly, which is what gives the 35×80×21 mm envelope its C 34.7 kN and C0 26.5 kN ratings (Pu 1.12 kN). SKF spells the double shield 307-2Z (suffix 2Z); the shields are non-contact, retain grease and block coarse debris but are not liquid-tight. Limiting speed 7600 r/min, mass 480 g. These bearings are built for high purely-radial loads at moderate speeds.
Typical equipment & failure modes
Common applications
- farm machinery and harvesters
- construction equipment drives
- hoists and winch gear trains
- eccentric and vibratory conveyors
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
- rolling-contact fatigue spalling once the catalogue L10 life is exceeded
- brinelling from static overload or hammer blows during mounting
Selection pitfalls — read before you substitute
- 307 uses the legacy SKF 200/300 numbering (light/heavy filling-slot series), not the modern 6200/6300 spelling; quote 307-2Z exactly when ordering replacements.
- Filling-slot bearings take heavy purely-radial load at moderate speed but little thrust; the 34.7/26.5 kN ratings assume radial loading — use deep-groove 6xxx where axial load matters.
- Shields on 307-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 7600 r/min: filling-slot cages and the slot geometry run cooler below that — overspeed drives cage wear and smearing.
- 307 uses the legacy SKF 200/300 numbering (light/heavy filling-slot series), not the modern 6200/6300 spelling; quote 307-2Z exactly when ordering replacements.
- Do not preload 307-ZZ to silence it: a deep-groove ball bearing is not angular-contact, and axial preload only raises temperature and shortens grease life.
Frequently asked questions
What are the dimensions of 307-ZZ?
Filling-slot bearing 307-2Z measures 35×80×21 mm (1.378×3.15×0.827 in), about 480 g.
What does the designation 307 mean?
It is the legacy 200/300 filling-slot numbering: series 300 and bore code 07 = 35 mm. Filling-slot bearings predate the 6xxx deep-groove spelling.
Can 307-ZZ take axial load?
Very little: the filling slots interrupt the raceway shoulders, so thrust towards the open slot side can unload or jam the balls. Use a standard deep-groove 6xxx bearing for combined loads.
Why use an old 300-series bearing instead of a 62xx?
For slow, heavy, purely-radial duty the extra balls give more capacity in the same bore, and the separable rings simplify assembly in blind housings; at high speed modern designs run better.
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.