7301 bearing: complete specifications & equivalents
The 7301 is a ISO 15 radial bearing sized 12 x 37 x 12 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Bore diameter d | 12 mm |
| Outer diameter D | 37 mm |
| Width B | 12 mm |
| Seal / shield | open |
| Internal clearance | CN / C3 available |
| Tolerance class | P0 |
| Cage | brass |
| Operating temperature | -40 to +150 °C |
| Mass (geometry estimate) | 59 g |
| Standard | ISO 15 |
| Catalog version | iso15-ed4-geometry |
| Last verified | 2026-09-24 |
Source: ISO 15 boundary-dimensions standard · extracted 2026-09-24
Standard-interchange bearing: dimensions per ISO 15; CN clearance, P0 tolerance and a stamped-steel cage are catalogue defaults unless the supplier states otherwise, and mass is a geometry-derived estimate. Brand catalogue load ratings and limiting speeds for 7301 are being backfilled — use the inquiry form for certified values.
Dimensions in inches & 7300-series range
| Bore d | 0.472 in |
|---|---|
| Outer diameter D | 1.457 in |
| Width B | 0.472 in |
| ISO bore code | 01 |
| Radial section height (D−d)/2 | 12.5 mm |
| Smallest bore in 7300-series | 10 mm |
| Largest outer diameter in 7300-series | 240 mm |
| Width range across 7300-series | 11–50 mm |
| Bore position in 7300-series (smallest first) | 2 of 23 |
| Bore above smallest 7300-series size | 2 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| 7301 | ISO 15 | full Dimensions and internal design equivalent — standard interchange. | ISO 15 boundary-dimension envelope; brand-specific OEM equivalents (NSK/FAG/NTN) 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 7301 model number is decoded
In the 7300-series (ISO 15 diameter series 3) the last two digits encode the bore: 7301 carries bore code 01 = 12 mm. Codes 00–03 follow the 10/12/15/17 mm exception table rather than code × 5. Outside diameter 37 mm and width 12 mm come from the ISO 15 boundary-dimensions general plan, shared with the 6301 deep-groove envelope. The '7' prefix marks a single-row angular-contact design with an asymmetric raceway and a nominal 40° contact angle (suffix C); a higher-angle variant carries more axial load, a 25° (E / A5) variant runs faster. For combined radial and axial load with a rotating inner ring on a 12 mm shaft, specify a j5 shaft seat with an H7 housing bore — verify against the load direction and magnitude, and pair two units (DB or DF) for bidirectional thrust.
Typical equipment & failure modes
Common applications
- hand tool rotors
- small precision gearboxes
- instrument spindles
- miniature pump rotors
Known failure patterns
- electric pitting in VFD-driven spindles without shaft grounding protection
- raceway spalling from axial overload exceeding the single-direction thrust rating
- preload loss after a paired set runs loose, letting the balls skid and smear the raceway
- raceway smearing under marginal lubrication at start-up before oil climb reaches the contact
Selection pitfalls — read before you substitute
- Bore codes 00–03 use the exception table: 7301 fits a 12 mm shaft — the code × 5 mnemonic does not apply below code 04.
- The 73xx medium section gains axial and radial rating at 12 mm bore through a 37 mm OD and 12 mm width; the heavier balls also trade away speed versus a 7201 angular contact.
- Preload class matters: a 7301 in a DB pair is supplied as preload class light (L) for speed or heavy (H) for rigidity; mixing unmarked bearings in a pair gives uneven preload and short life.
- Mounting direction is fixed by the asymmetric raceway — the marked side faces the axial load; installing 7301 backwards loads the low shoulder and displaces the balls out of the raceway.
Frequently asked questions
What are the dimensions of a 7301 angular-contact bearing?
A 7301 single-row angular-contact ball bearing has a 12 mm bore, 37 mm outer diameter and 12 mm width (0.472 × 1.457 × 0.472 in), per ISO 15 boundary dimensions. It is an open bearing with a nominal 40° contact angle. Geometry-based estimated mass is about 59 g for a brass-cage unit; catalogue masses vary with cage and ball complement.
Why does 7301 not follow the bore-code × 5 rule?
Codes 00–03 use the exception table (10, 12, 15 and 17 mm): 7301 with code 01 has a 12 mm bore. The code × 5 convention starts at code 04 (20 mm).
What is the contact angle of 7301?
The nominal contact angle is 40° (suffix C): a higher angle carries more axial load but limits speed. A 25° (suffix E or A5) variant runs faster and is preferred for high-speed spindles; a 15° (suffix C7) version exists for very-high-speed duty. Confirm the angle and ball complement in the supplier catalogue.
Can a single 7301 take axial load in both directions?
No. A single-row angular-contact bearing carries axial load in one direction only. For bidirectional thrust, mount a matched pair — DB (back-to-back) for a rigid, moment-resisting arrangement with preload class light (L) for speed or heavy (H) for stiffness, DF (face-to-face) for thermal expansion tolerance, or DT (tandem) to share one-direction load.
How does 7301 compare with a deep-groove 6301?
Both share the 12×37×12 mm ISO 15 envelope (12.5 mm radial section), but the angular-contact 7301 has an asymmetric raceway and 40° contact angle: it carries higher combined axial+radial load and runs with controlled preload, but is slower, noisier and needs pairing — it is not a drop-in replacement for a deep-groove 6301.
Reviewed & verified by the MPN Base engineering desk against source catalog iso15-ed4-geometry on 2026-09-24. Read our editorial & correction policy.