30307 bearing: complete specifications & equivalents
The 30307 is a ISO 355 radial bearing sized 35 x 80 x 22.75 mm (bore x OD x width). 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 | 22.75 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | steel, stamped ribbon (J-type) |
| Basic dynamic load rating C | 88.9 kN |
| Basic static load rating C0 | 73.5 kN |
| Fatigue load limit Pu | 8.3 kN |
| Reference speed (thermal) | 7500 rpm |
| Limiting speed (mechanical) | 9000 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 510 g |
| Manufacturer designation | SKF 30307 |
| Standard | ISO 355 |
| Catalog version | SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 8.1 metric single-row TRB |
| Last verified | 2026-09-26 |
Source: catalog reference (SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 8.1 metric single-row TRB) · extracted 2026-09-26
Parameters extracted from the official SKF Rolling Bearings catalogue (SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 8.1 metric single-row TRB); 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 & 30300-series range
| Bore d | 1.378 in |
|---|---|
| Outer diameter D | 3.15 in |
| Width B | 0.896 in |
| ISO bore code | 07 |
| Radial section height (D−d)/2 | 22.5 mm |
| Smallest bore in 30300-series | 15 mm |
| Largest outer diameter in 30300-series | 500 mm |
| Width range across 30300-series | 14.25–105 mm |
| Bore position in 30300-series (smallest first) | 6 of 32 |
| Bore above smallest 30300-series size | 20 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| 30307 | ISO 15 | full Dimensions and internal design equivalent — standard interchange. | ISO 355 boundary-dimension envelope; brand-specific OEM equivalents (NSK/FAG/NTN) pending multi-source data. |
| 30307-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. |
| 30307R | SKF | partial Main dimensions match; tolerances, seals or internal clearance differ. | Flanged-cup variant of this base bearing: same d/D/T boundary, different housing location concept — not a drop-in substitute where the flange is the axial register. |
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 30307 model number is decoded
In SKF catalogue PUB BU/P1 17000, 30307 appears as SKF 30307: an open, single-row tapered roller bearing in the heavy-OD section of the 30300 dimension series, supplied with a pressed-steel cage as standard.Reading the designation: the leading 3 marks a single-row tapered roller bearing, the 03 is the ISO 355 diameter/width series (heavy-OD section), and the last two digits encode the 35 mm bore; the 80 mm OD and 22.75 mm width follow the ISO 355 general plan. The SKF catalogue adds the ISO 355 dimension-series code after the bare number (e.g. 2FB); it is the dimensional series, not a separate part number. With C 88.9 kN and C0 73.5 kN, the 30307 pair-sizing check is dominated by the axial share: keep the equivalent load P below the rating at the required L10, remembering one bearing alone cannot cover reversing thrust at 9,000 r/min. Mounting practice for 30307: the rotating cone takes the interference fit (k5 on a 35 mm shaft), the cup slides for axial location, and reversing-thrust duty demands a paired O/X set rather than one bearing.
Typical equipment & failure modes
Common applications
- pump and compressor shafts
- machine-tool spindles
- belt-driven fan and blower shafts
- axle-boxes in material-handling equipment
Known failure patterns
- cup or cone misalignment when the separable rings are not seated square during mounting
- loose cup rotation in the housing when the specified press fit is not achieved
- axial overload spalling at the roller-rib contact beyond the single-row thrust rating
- preload loss as the mounted pair relaxes, letting rollers skid and smear the raceways
- cage pocket scoring when the bearing starts cold with grease of too-high base-oil viscosity
- hard-particle indentation of the tapered raceway in unfiltered oil
Selection pitfalls — read before you substitute
- On this 35 mm bore, interference and temperature rise consume clearance inside a preloaded pair; calculate the residual clearance after mounting and at operating temperature — an over-tight 30307 pair heats, loses setting control and smears the roller-rib contact.
- The 303 series at 35 mm bore (80×22.75 mm) carries a larger OD and higher capacity than 30207 at the same bore; the bigger section runs hotter, so re-check the 9,000 r/min speed ceiling and shoulder diameters before substituting.
- O (back-to-back) pairs are stiffer against moments, X (face-to-face) pairs tolerate misalignment and thermal growth better; choosing the arrangement from the 2D drawing rather than the actual shaft thermal expansion is a common 30307 mounting error.
- Setting is a design value, not an assembly feel: excessive preload in the 30307 pair raises operating temperature and can trigger thermal runaway, while too little lets the rollers skid and smear the raceway under light load.
- The pressed-steel cage is rated for standard industrial service; sustained running above the limiting speed or with degraded lubricant wears the cage pockets — inspect the cage at every relubrication interval.
- The 88.9/73.5 kN ratings are SKF catalogue 17000 values for the basic execution; SKF can revise internal geometry without changing the order number, so keep the catalogue version (PUB BU/P1 17000/1 EN, 2018) with the specification and re-verify for critical drives.
- SKF lists several executions of 30307 (basic, B steeper angle, Q/J2 clearance variants); they are not interchangeable order numbers — quote the full SKF 30307 designation when purchasing and match the execution to the mounting arrangement.
Frequently asked questions
What are the dimensions and catalogue data of 30307?
The SKF 30307 is a single-row tapered roller bearing with 35 mm bore, 80 mm outer diameter and 22.75 mm width (1.378 × 3.15 × 0.896 in) per ISO 355. From SKF catalogue PUB BU/P1 17000: basic dynamic load rating C 88.9 kN, C0 73.5 kN, fatigue load limit Pu 8.3 kN, reference speed 7,500 r/min, limiting speed 9,000 r/min, mass about 510 g. It is an open, separable bearing with a pressed-steel cage.
How does the 30307 bore code work?
The last two digits of 30307 are bore code 07, so 07 × 5 = 35 mm bore. The 80 mm OD and 22.75 mm width come from the ISO 355 dimension-series plan, shared with other tapered bearings of the same code.
What do the 30307 series and basic execution designations mean?
The leading 3 marks a single-row tapered roller bearing; the second digit 03 is the ISO 355 series (heavy-OD section). The SKF catalogue lists the ISO 355 dimension-series code after the bare number. A steeper-contact-angle variant (B suffix) is a different order number and is not interchangeable with the basic execution.
Can a single 30307 take axial load in both directions?
No — one single-row tapered roller bearing reacts thrust in one direction only, and under radial load its contact angle induces an axial force. Use two bearings as a matched pair: O (back-to-back) for a rigid, moment-resisting arrangement, X (face-to-face) where thermal expansion must be tolerated, or tandem where one-direction thrust is shared.
How does 30307 compare with a ball bearing of the same bore?
A tapered roller bearing has line contact and a steep contact angle: much higher combined axial-plus-radial capacity and shock resistance than a ball bearing of the same bore, at the cost of speed, one-direction thrust, mandatory pairing for reversing loads and a minimum axial load requirement. A ball bearing cannot be dropped into a combined-load 30307 position and vice versa — verify load direction, Fa/Fr ratio and speed before substituting.
Reviewed & verified by the MPN Base engineering desk against source catalog SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 8.1 metric single-row TRB on 2026-09-26. Read our editorial & correction policy.