7300-NTN bearing: complete specifications & equivalents
The 7300-NTN is a ISO 15 radial bearing sized 10 x 35 x 11 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | NTN |
| Bore diameter d | 10 mm |
| Outer diameter D | 35 mm |
| Width B | 11 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | steel, stamped ribbon (J-type) |
| Basic dynamic load rating C | 11.2 kN |
| Basic static load rating C0 | 4.95 kN |
| Fatigue load limit Pu | 0.39 kN |
| Limiting speed (mechanical) | 26000 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 40 g |
| Manufacturer designation | NTN 7300 |
| Standard | ISO 15 |
| Catalog version | NTN Ball and Roller Bearings CAT.No.2203E |
| Last verified | 2026-10-01 |
Source: catalog reference (NTN Ball and Roller Bearings CAT.No.2203E) · extracted 2026-10-01
Parameters extracted from the official NTN Ball and Roller Bearings catalogue (NTN Ball and Roller Bearings CAT.No.2203E); NTN® is a trademark of NTN Corporation, used here for identification only — mpnbase is not an authorized NTN distributor. Boundary dimensions are ISO 15 interchangeable; current production values may differ, verify at ntnglobal.com.
Dimensions in inches & 7300-series range
| Bore d | 0.394 in |
|---|---|
| Outer diameter D | 1.378 in |
| Width B | 0.433 in |
| ISO bore code | 00 |
| Radial section height (D−d)/2 | 12.5 mm |
| Smallest bore in 7300-series | 10 mm |
| Largest outer diameter in 7300-series | 420 mm |
| Width range across 7300-series | 11–80 mm |
| Bore position in 7300-series (smallest first) | 1 of 32 |
| Bore above smallest 7300-series size | 0 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| 7300 | GENERIC-ISO | 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. |
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 7300-NTN model number is decoded
At 10 x 35 x 11 mm, NTN 7300 sits in the heavy-duty 7300 single-row family of the angular-contact programme. Decoding 7300: 73 is the single-row dimension series (heavy-duty 7300 single-row family), with 00 encodes the 10 mm bore (bore code x 5); with no letter after the digits it is the standard 30 deg contact-angle execution — the 40 deg version carries a B. Catalogue mass is about 40 g, which at this 12.5 mm radial section keeps the bearing comfortably inside high-speed spindle weight budgets. If the duty is mainly high speed with modest thrust, the 7900-series cross-section is the lighter alternative; if thrust dominates, the 7300-series section carries more. Heat-mounting to 80-90 deg C is the clean route onto a 10 mm shaft; drive-fits through the balls transmit force through the contact ellipse and can brinell it.
Typical equipment & failure modes
Common applications
- small machine-tool spindle and live-centre positions
- high-speed router, grinder and woodworking spindles
- small pump and compressor shafts with combined load
- servo and stepper motor shafts with axial preload
Known failure patterns
- impact brinelling dents on the 30 deg contact path after a shaft-side hammer blow during mounting, because axial shock travels straight through the contact angle
- loss of preload after housing-fret or shaft creep, leaving the pair loose — ball skidding, cage rattle and a falling natural frequency follow
- machined-cage land scoring when a high-speed spindle runs past its grease rating and the cage runs dry on its guidance surface
- contamination-induced denting — hard particles rolled into the contact ellipse become the initiation points for surface fatigue
- current-erosion pitting on VFD-driven motor shafts, first visible as a grey frosted band across both raceways
Selection pitfalls — read before you substitute
- At 10 mm bore the rings are thin-sectioned: press force must go through the ring being fitted, never through the balls, or the first damage is already in the raceway before the machine runs.
- The standard 30 deg bearing and its B (40 deg) sibling share the envelope; picking between them is a load-direction decision, not a quality upgrade.
- Grease rated for deep-groove motor duty is not automatically right at 26,000 r/min with preload; check the grease speed factor against the catalogue figure.
- Grease rated for deep-groove motor duty is not automatically right at 26,000 r/min with preload; check the grease speed factor against the catalogue figure.
- If the application vibrates at standstill (transport, idle machine next to a running line), specify protection: the contact ellipse of a preloaded bearing false-brinells faster than a loose one.
- The 11.2/4.95 kN ratings and 0.39 kN Pu here are NTN Ball and Roller Bearings CAT.No.2203E figures for 7300; internal geometry legitimately differs between manufacturers, so re-verify ratings, contact angle and suffix before substituting another make on a rated drive.
Frequently asked questions
What are the dimensions and catalogue ratings of NTN 7300?
7300 is a single-row angular contact ball bearing to ISO 15: 10 mm bore, 35 mm outside diameter, 11 mm width (0.394 x 1.378 x 0.433 in). From NTN Ball and Roller Bearings CAT.No.2203E: C 11.2 kN, C0 4.95 kN and a 0.39 kN fatigue load limit Pu; the grease limiting speed is 26,000 r/min and the oil rating 34,000 r/min; mass about 40 g.
How is the 7300 designation structured?
73 is the single-row dimension series (heavy-duty 7300 single-row family); 00 encodes the 10 mm bore (bore code x 5); with no letter after the digits it is the standard 30 deg contact-angle execution — the 40 deg version carries a B. The 35 mm OD and 11 mm width follow the ISO 15 boundary-dimension plan for that series.
Which axial direction does 7300 support?
One 7300 alone takes thrust in one direction only, along its 30 deg contact angle; reversing thrust calls for a second bearing or a factory-matched DB/DF/DT pair (the catalogue right-hand columns list the paired ratings). Radial load is always carried as a combined load through the angled contact.
What lubrication speeds does NTN print for 7300?
Per NTN Ball and Roller Bearings CAT.No.2203E, the grease limiting speed is 26,000 r/min and the oil rating 34,000 r/min. These are catalogue ceilings for a correctly mounted bearing with the stated lubricant; preload, fill quantity, ambient heat and paired arrangements all move the real limit.
What should be checked before substituting another make for 7300?
The 10/35/11 mm envelope is ISO 15 interchangeable, but internal geometry — contact angle, osculation, cage and shoulder details — is maker-specific. Re-verify C 11.2 kN / C0 4.95 kN, the speed figures, contact angle and suffix meaning against the donor catalogue before swapping on a rated drive.
Reviewed & verified by the MPN Base engineering desk against source catalog NTN Ball and Roller Bearings CAT.No.2203E on 2026-10-01. Read our editorial & correction policy.