7313B bearing: complete specifications & equivalents
The 7313B is a ISO 15 radial bearing sized 65 x 140 x 33 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | NTN |
| Bore diameter d | 65 mm |
| Outer diameter D | 140 mm |
| Width B | 33 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | steel, stamped ribbon (J-type) |
| Basic dynamic load rating C | 113 kN |
| Basic static load rating C0 | 75.5 kN |
| Fatigue load limit Pu | 5.85 kN |
| Limiting speed (mechanical) | 4700 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 2150 g |
| Manufacturer designation | NTN 7313B |
| 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 | 2.559 in |
|---|---|
| Outer diameter D | 5.512 in |
| Width B | 1.299 in |
| ISO bore code | — |
| Radial section height (D−d)/2 | 37.5 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) | 14 of 32 |
| Bore above smallest 7300-series size | 55 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| 7313B | ISO 15 | full Dimensions and internal design equivalent — standard interchange. | ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the 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 7313B model number is decoded
7313B is the 65 mm bore member of NTN's heavy-duty 7300 single-row family, with a 140 mm outside diameter and 33 mm section width. NTN builds the number from 73 is the single-row dimension series (heavy-duty 7300 single-row family), then 13 encodes the 65 mm bore (bore code x 5), and the trailing B marks the 40 deg contact-angle execution (the no-letter standard bearing works at 30 deg). The radial section height here is 37.5 mm, and the catalogue couples that with C 113 kN / C0 75.5 kN. For a 65 mm shaft with combined load, the practical shortlist is this series, its 7200-series lighter section, and — where thrust reverses — a back-to-back pair rather than a single row. Mount with the thrust against the marked face: the contact angle runs from the low shoulder of the inner ring to the high shoulder of the outer ring, and reversing it throws the capacity away.
Typical equipment & failure modes
Common applications
- paper-machine roll and calendar drives
- extruder and mixer gearbox output shafts
- mining conveyor head-shaft positions
- marine auxiliary and winch gearbox shafts
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
- thermal runaway from excessive preload: the pair runs hot, grease darkens and the contact ellipse spreads until the raceways smear
- machined-cage land scoring when a high-speed spindle runs past its grease rating and the cage runs dry on its guidance surface
- current-erosion pitting on VFD-driven motor shafts, first visible as a grey frosted band across both raceways
- flaking that starts at the raceway shoulder on the thrust-loaded side when axial load repeatedly exceeds the design share
Selection pitfalls — read before you substitute
- Bearings of 65 mm bore arrive heavy enough that handling damage (dents from slings, tilting on the shaft) is a real failure precursor — use proper lifting and heating kit.
- The 40 deg B-execution raises axial capacity but lowers the speed ceiling — do not copy the standard-bearing speed and preload settings onto it.
- The 4,700 r/min speed figure assumes the catalogue lubrication state and a correctly set pair; real limits drop fast with excess grease fill or heavy preload.
- Grease rated for deep-groove motor duty is not automatically right at 4,700 r/min with preload; check the grease speed factor against the catalogue figure.
- 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 113/75.5 kN ratings and 5.85 kN Pu here are NTN Ball and Roller Bearings CAT.No.2203E figures for 7313B; 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 7313B?
7313B is a single-row angular contact ball bearing to ISO 15: 65 mm bore, 140 mm outside diameter, 33 mm width (2.559 x 5.512 x 1.299 in). From NTN Ball and Roller Bearings CAT.No.2203E: C 113 kN, C0 75.5 kN and a 5.85 kN fatigue load limit Pu; the grease limiting speed is 4,700 r/min and the oil rating 6,300 r/min; mass about 2150 g.
How is the 7313B designation structured?
73 is the single-row dimension series (heavy-duty 7300 single-row family); 13 encodes the 65 mm bore (bore code x 5), and the trailing B marks the 40 deg contact-angle execution (the no-letter standard bearing works at 30 deg). The 140 mm OD and 33 mm width follow the ISO 15 boundary-dimension plan for that series.
Which axial direction does 7313B support?
One 7313B alone takes thrust in one direction only, along its 40 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 7313B?
Per NTN Ball and Roller Bearings CAT.No.2203E, the grease limiting speed is 4,700 r/min and the oil rating 6,300 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 7313B?
The 65/140/33 mm envelope is ISO 15 interchangeable, but internal geometry — contact angle, osculation, cage and shoulder details — is maker-specific. Re-verify C 113 kN / C0 75.5 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.