7301-NTN bearing: complete specifications & equivalents
The 7301-NTN 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 |
|---|---|
| Brand | NTN |
| Bore diameter d | 12 mm |
| Outer diameter D | 37 mm |
| Width B | 12 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | steel, stamped ribbon (J-type) |
| Basic dynamic load rating C | 12.4 kN |
| Basic static load rating C0 | 5.25 kN |
| Fatigue load limit Pu | 0.41 kN |
| Limiting speed (mechanical) | 23000 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 44 g |
| Manufacturer designation | NTN 7301 |
| 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 | 0.472 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 | 420 mm |
| Width range across 7300-series | 11–80 mm |
| Bore position in 7300-series (smallest first) | 2 of 32 |
| Bore above smallest 7300-series size | 2 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| 7301 | SKF | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 12×37×12 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting. |
| 7301-BE-2RZP | SKF | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 12×37×12 mm envelope per ISO 15; seal variant (OPEN vs RSR) and load ratings differ — confirm sealing and rating before substituting. |
| 7301-BEP | SKF | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 12×37×12 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting. |
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-NTN model number is decoded
7301 is the 12 mm bore member of NTN's heavy-duty 7300 single-row family, with a 37 mm outside diameter and 12 mm section width. The designation breaks down as 73 is the single-row dimension series (heavy-duty 7300 single-row family); 01 encodes the 12 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 radial section height here is 12.5 mm, and the catalogue couples that with C 12.4 kN / C0 5.25 kN. Where the same envelope must also be sealed, or where mounting mistakes are likely, compare with the double-row 52/53 catalogue pages before fixing the bill of materials. Heat-mounting to 80-90 deg C is the clean route onto a 12 mm shaft; drive-fits through the balls transmit force through the contact ellipse and can brinell it.
Typical equipment & failure modes
Common applications
- small pump and compressor shafts with combined load
- servo and stepper motor shafts with axial preload
- bicycle and motorcycle wheel and steering positions
- small gearbox pinion shafts with helical gears
Known failure patterns
- false brinelling on the raceway contact ellipses when a preloaded spindle sits vibrating at standstill — visible as evenly spaced flute-like wear at ball pitch
- 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
- flaking that starts at the raceway shoulder on the thrust-loaded side when axial load repeatedly exceeds the design share
- lubricant starvation scoring at the ball/raceway contact when grease volume or relubrication interval is guessed instead of calculated
Selection pitfalls — read before you substitute
- At 12 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.
- A 7301 mounted the wrong way round still turns smoothly by hand; the failure shows up weeks later as raceway flaking on the unloaded-looking side.
- On a 12 mm shaft, an interference fit eats internal clearance; skipping the clearance/preload recalculation is the classic cause of a new bearing running 20 deg C hotter than the drawing suggests.
- A single-row angular contact left loose on the shaft to "help assembly" will fret the seat: the contact angle keeps driving the ring axially under load.
- The 12.4/5.25 kN ratings and 0.41 kN Pu here are NTN Ball and Roller Bearings CAT.No.2203E figures for 7301; 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 7301?
7301 is a single-row angular contact ball bearing to ISO 15: 12 mm bore, 37 mm outside diameter, 12 mm width (0.472 x 1.457 x 0.472 in). From NTN Ball and Roller Bearings CAT.No.2203E: C 12.4 kN, C0 5.25 kN and a 0.41 kN fatigue load limit Pu; the grease limiting speed is 23,000 r/min and the oil rating 30,000 r/min; mass about 44 g.
How is the 7301 designation structured?
73 is the single-row dimension series (heavy-duty 7300 single-row family); 01 encodes the 12 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 37 mm OD and 12 mm width follow the ISO 15 boundary-dimension plan for that series.
Which axial direction does 7301 support?
One 7301 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 7301?
Per NTN Ball and Roller Bearings CAT.No.2203E, the grease limiting speed is 23,000 r/min and the oil rating 30,000 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 7301?
The 12/37/12 mm envelope is ISO 15 interchangeable, but internal geometry — contact angle, osculation, cage and shoulder details — is maker-specific. Re-verify C 12.4 kN / C0 5.25 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.