6379-6320 bearing: complete specifications & equivalents
The 6379-6320 is a ANSI ABMA 19.2 radial bearing sized 65.088 x 135.755 x 53.975 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | NTN |
| Bore diameter d | 65.088 mm |
| Outer diameter D | 135.755 mm |
| Width B | 53.975 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | steel |
| Basic dynamic load rating C | 310 kN |
| Basic static load rating C0 | 380 kN |
| Limiting speed (mechanical) | 2900 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 3710 g |
| Manufacturer designation | NTN 4T-6379/6320 |
| Standard | ANSI ABMA 19.2 |
| Catalog version | NTN 2203E 2026-09-25 |
| Last verified | 2026-10-01 |
Source: catalog reference (NTN 2203E 2026-09-25) · extracted 2026-10-01
Parameters extracted from the official NTN Ball and Roller Bearings catalogue (NTN 2203E 2026-09-25); 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 & 4t-inch-series range
| Bore d | 2.563 in |
|---|---|
| Outer diameter D | 5.345 in |
| Width B | 2.125 in |
| ISO bore code | — |
| Radial section height (D−d)/2 | 35.3 mm |
| Smallest bore in 4t-inch-series | 12.7 mm |
| Largest outer diameter in 4t-inch-series | 260 mm |
| Width range across 4t-inch-series | 10.998–77.788 mm |
| Bore position in 4t-inch-series (smallest first) | 83 of 148 |
| Bore above smallest 4t-inch-series size | 52.38799999999999 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| 6379-K-6320 | SKF | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 65.088×135.755×53.975 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 6379-6320 model number is decoded
In NTN Ball and Roller Bearings CAT.No.2203E, the order number 4T-6379/6320 denotes the pure-numeric inch family of NTN inch tapered roller bearings — cone 6379 and cup 6320 delivered as a matched, separable pair of 65.088 mm bore and 135.755 mm outside diameter. Letter prefixes inherited from the inch convention mark the load family: LM reads as light-medium, HM as heavy-medium, LL as extra-light, J-prefixed codes as metric-envelope families — 6379 sits in the pure-numeric inch family. The 4.8 kN of dynamic capacity per millimetre of bore summarises the 310 kN rating over the 65.088 mm bore — sanity-check any interchange candidate against this ratio and the 53.975 mm T. Cup-side note for 6320: within the pure-numeric inch family tables the 6379 cone is listed against several cup options, and it is the cup that fixes the 135.755 mm OD and the 53.975 mm assembled width — quote the full 6379/6320 pair, never the cone alone. Mount the 65.088 mm cone with an induction heater (max 120 °C) and press the 135.755 mm cup with a sleeve; driving either ring through the rollers brinells the raceways.
Typical equipment & failure modes
Common applications
- plant gearboxes on inch-dimensioned shaft lines
- large conveyor head pulleys in bulk-handling plant
- paper-machine and calender roll supports
- off-highway and forestry machine axles
Known failure patterns
- rib-face scoring when the thrust share of the combined load exceeds what the cone rib of this size carries
- preload loss and noise after one bearing of the adjusted pair is replaced without resetting end play
- false brinelling on a stationary pair exposed to vibration during transport or standby
- cage damage from a mounting blow transmitted through the roller complement
- rolling-contact fatigue spalling after the catalogue L10 life at the actual combined load
Selection pitfalls — read before you substitute
- Mount the 65.088 mm cone by induction heating (max 120 °C) and the 135.755 mm cup with a press sleeve; at 3710 g a cocked ring brinells the raceway directly.
- The pure-numeric inch family at 65.088 mm bore (135.755×53.975 mm assembled) is one of several inch families sharing similar bores; cross-series swaps change OD, T and contact angle, so match the full 6379/6320 reference at purchase.
- ABMA makes the 65.088×135.755 mm envelope interchangeable, not the ratings: NTN prints 310/380 kN for this execution and another make of the same number can differ in roller complement.
- Open 4T-6379/6320 sets have no seals: a hub or gearbox needs external sealing or the 2,900 r/min grease figure is meaningless once water reaches the cone rib.
- Replacing one half of an adjusted pair without resetting end play negates the 53.975 mm T logic: re-adjust the set and re-verify the contact pattern rather than reusing the old spacer stack.
- The 310/380 kN ratings here are NTN Ball and Roller Bearings CAT.No.2203E figures for 4T-6379/6320; internal geometry legitimately differs between inch-series makers, so re-verify ratings, adjustment and the exact cone/cup references before substituting another brand on a rated drive.
Frequently asked questions
What are the dimensions and catalogue ratings of NTN 4T-6379/6320?
4T-6379/6320 is an inch-series single-row tapered roller bearing to the ABMA boundary plan: 65.088 mm bore (2.563 in), 135.755 mm outside diameter and 53.975 mm assembled width T (5.345 × 2.125 in). From NTN Ball and Roller Bearings CAT.No.2203E: C 310 kN, C0 380 kN, grease limiting speed 2,900 r/min, oil speed 3,800 r/min, mass about 3710 g. It is an open, separable cone/cup set with a pressed-steel cage.
Are the cone and cup of 4T-6379/6320 interchangeable separately?
Yes — ABMA inch parts are individually interchangeable: the 6379 cone or the 6320 cup can be replaced by an identical reference from NTN or another ABMA-dimensioned maker. Pairing the cone with a different cup reference is a different catalogue row: OD, assembled T and the 310/380 kN ratings change with the cup.
What is the difference between 4T-6379/6320 and a metric ISO 355 tapered bearing?
4T-6379/6320 follows the ABMA inch boundary plan with cone/cup references; ISO 355 bearings use metric dimension-series numbers (302, 322, …). Even where a metric size looks close to 65.088×135.755×53.975 mm, the envelopes and contact angles differ — the two systems are not drop-in interchangeable; check every boundary value before substituting.
What does the 4T prefix on 4T-6379/6320 mean?
4T is NTN's tapered roller bearing quality mark, stamped on cone and cup in the factory. It identifies NTN's 4T programme and is not a dimension or variant code, so interchange lists quote the bare 6379/6320 references; the 4T spelling is retained among this page's search aliases.
Why does 4T-6379/6320 list two speeds, 2,900 and 3,800 r/min?
The lower figure, 2,900 r/min, is the grease-lubricated limiting speed — the mechanical ceiling for the cage, rollers and cone-rib contact. With oil lubrication NTN rates 4T-6379/6320 at 3,800 r/min because oil removes rib-contact heat better. Real limits still depend on pair adjustment, oil flow and cooling.
Reviewed & verified by the MPN Base engineering desk against source catalog NTN 2203E 2026-09-25 on 2026-10-01. Read our editorial & correction policy.