387-382A-NTN bearing: complete specifications & equivalents
The 387-382A-NTN is a ANSI ABMA 19.2 radial bearing sized 57.15 x 96.838 x 21 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | NTN |
| Bore diameter d | 57.15 mm |
| Outer diameter D | 96.838 mm |
| Width B | 21 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | steel |
| Basic dynamic load rating C | 86.5 kN |
| Basic static load rating C0 | 96.5 kN |
| Limiting speed (mechanical) | 3700 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 582 g |
| Manufacturer designation | NTN 4T-387/382A |
| 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 | 2.25 in |
|---|---|
| Outer diameter D | 3.813 in |
| Width B | 0.827 in |
| ISO bore code | 87 |
| Radial section height (D−d)/2 | 19.8 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) | 72 of 148 |
| Bore above smallest 4t-inch-series size | 44.45 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| 387-382 | SKF | verify Commonly quoted cross reference; confirm against the target catalog before ordering. | Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue. |
| 387-382A | SKF | verify Commonly quoted cross reference; confirm against the target catalog before ordering. | Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue. |
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 387-382A-NTN model number is decoded
NTN supplies this 2.25 in (57.15 mm) shaft position as 4T-387/382A: cone 387, cup 382A, profiled rollers and a pressed-steel cage, rated 86.5 kN basic dynamic and 96.5 kN static. Cone and cup of 4T-387/382A are separately stocked parts: a worn 382A cup can be replaced against the existing 387 cone, provided the new cup carries the identical reference — pairing across references changes the 21 mm assembled width and the rating. Catalogue mass of the 4T-387/382A cone-plus-cup set is 582 g; shaft and housing shoulders must carry that mass square to the axis during fitting. Cup-side note for 382A: within the pure-numeric inch family tables the 387 cone is listed against several cup options, and it is the cup that fixes the 96.838 mm OD and the 21 mm assembled width — quote the full 387/382A pair, never the cone alone. The rollers run with their large ends against the cone's guide rib; lubricant must reach that rib face of 4T-387/382A, not only the raceway, or the pair smears on the first overloaded start.
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
- false brinelling on a stationary pair exposed to vibration during transport or standby
- preload loss and noise after one bearing of the adjusted pair is replaced without resetting end play
- cage fatigue when the pair runs continuously near the grease limiting speed without oil cooling
- brinell marks on cone and cup raceways from impact during handling or hammer fitting
Selection pitfalls — read before you substitute
- Mount the 57.15 mm cone by induction heating (max 120 °C) and the 96.838 mm cup with a press sleeve; at 582 g a cocked ring brinells the raceway directly.
- The pure-numeric inch family at 57.15 mm bore (96.838×21 mm assembled) is one of several inch families sharing similar bores; cross-series swaps change OD, T and contact angle, so match the full 387/382A reference at purchase.
- Replacing one half of an adjusted pair without resetting end play negates the 21 mm T logic: re-adjust the set and re-verify the contact pattern rather than reusing the old spacer stack.
- Fit selection follows the rotating ring: a rotating cone on a 57.15 mm shaft takes a k5/m5 seat, and a rotating cup reverses the logic — decide from the load diagram, not from habit.
- Open 4T-387/382A sets have no seals: a hub or gearbox needs external sealing or the 3,700 r/min grease figure is meaningless once water reaches the cone rib.
- The 86.5/96.5 kN ratings here are NTN Ball and Roller Bearings CAT.No.2203E figures for 4T-387/382A; 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-387/382A?
4T-387/382A is an inch-series single-row tapered roller bearing to the ABMA boundary plan: 57.15 mm bore (2.25 in), 96.838 mm outside diameter and 21 mm assembled width T (3.813 × 0.827 in). From NTN Ball and Roller Bearings CAT.No.2203E: C 86.5 kN, C0 96.5 kN, grease limiting speed 3,700 r/min, oil speed 5,000 r/min, mass about 582 g. It is an open, separable cone/cup set with a pressed-steel cage.
Are the cone and cup of 4T-387/382A interchangeable separately?
Yes — ABMA inch parts are individually interchangeable: the 387 cone or the 382A 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 86.5/96.5 kN ratings change with the cup.
What is the difference between 4T-387/382A and a metric ISO 355 tapered bearing?
4T-387/382A 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 57.15×96.838×21 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-387/382A 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 387/382A references; the 4T spelling is retained among this page's search aliases.
Why does 4T-387/382A list two speeds, 3,700 and 5,000 r/min?
The lower figure, 3,700 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-387/382A at 5,000 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.