47678-47620-NTN bearing: complete specifications & equivalents
The 47678-47620-NTN is a ANSI ABMA 19.2 radial bearing sized 76.2 x 133.35 x 33.338 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | NTN |
| Bore diameter d | 76.2 mm |
| Outer diameter D | 133.35 mm |
| Width B | 33.338 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | steel |
| Basic dynamic load rating C | 170 kN |
| Basic static load rating C0 | 235 kN |
| Limiting speed (mechanical) | 2600 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 1920 g |
| Manufacturer designation | NTN 4T-47678/47620 |
| 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 | 3 in |
|---|---|
| Outer diameter D | 5.25 in |
| Width B | 1.313 in |
| ISO bore code | — |
| Radial section height (D−d)/2 | 28.6 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) | 94 of 148 |
| Bore above smallest 4t-inch-series size | 63.5 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| 47678-47620 | SKF | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 76.2×133.35×33.338 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 47678-47620-NTN model number is decoded
NTN supplies this 3 in (76.2 mm) shaft position as 4T-47678/47620: cone 47678, cup 47620, profiled rollers and a pressed-steel cage, rated 170 kN basic dynamic and 235 kN static. Cone and cup of 4T-47678/47620 are separately stocked parts: a worn 47620 cup can be replaced against the existing 47678 cone, provided the new cup carries the identical reference — pairing across references changes the 33.338 mm assembled width and the rating. Grease relubrication at the 2,600 r/min limiting speed targets the cone-rib contact; sustaining 3,500 r/min needs an oil supply directed at the large roller ends. The printed 170/235 kN ratings belong to the assembled 47678+47620 pair; a sibling row using the same cone with a different cup carries its own rating row because the raceway track shifts with the cup. A single-row tapered bearing reacts thrust in one direction only; 4T-47678/47620 is adjusted against a second bearing so the shaft is located in both directions.
Typical equipment & failure modes
Common applications
- paper-machine and calender roll supports
- off-highway and forestry machine axles
- marine winch and deck-machinery shafts
- crusher and screening-plant eccentric shafts
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
- pressed-steel cage pocket wear from roller skid at light radial load and high speed
- water-induced pitting when the open bearing sees washdown without external seals
Selection pitfalls — read before you substitute
- Mount the 76.2 mm cone by induction heating (max 120 °C) and the 133.35 mm cup with a press sleeve; at 1920 g a cocked ring brinells the raceway directly.
- The pure-numeric inch family at 76.2 mm bore (133.35×33.338 mm assembled) is one of several inch families sharing similar bores; cross-series swaps change OD, T and contact angle, so match the full 47678/47620 reference at purchase.
- Open 4T-47678/47620 sets have no seals: a hub or gearbox needs external sealing or the 2,600 r/min grease figure is meaningless once water reaches the cone rib.
- Fit selection follows the rotating ring: a rotating cone on a 76.2 mm shaft takes a k5/m5 seat, and a rotating cup reverses the logic — decide from the load diagram, not from habit.
- Grease packs must leave free volume inside the 33.338 mm-wide set; over-greasing a pair churning near the oil-band speed of 3,500 r/min raises temperature and destroys the setting.
- The 170/235 kN ratings here are NTN Ball and Roller Bearings CAT.No.2203E figures for 4T-47678/47620; 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-47678/47620?
4T-47678/47620 is an inch-series single-row tapered roller bearing to the ABMA boundary plan: 76.2 mm bore (3 in), 133.35 mm outside diameter and 33.338 mm assembled width T (5.25 × 1.313 in). From NTN Ball and Roller Bearings CAT.No.2203E: C 170 kN, C0 235 kN, grease limiting speed 2,600 r/min, oil speed 3,500 r/min, mass about 1920 g. It is an open, separable cone/cup set with a pressed-steel cage.
Are the cone and cup of 4T-47678/47620 interchangeable separately?
Yes — ABMA inch parts are individually interchangeable: the 47678 cone or the 47620 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 170/235 kN ratings change with the cup.
What is the difference between 4T-47678/47620 and a metric ISO 355 tapered bearing?
4T-47678/47620 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 76.2×133.35×33.338 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-47678/47620 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 47678/47620 references; the 4T spelling is retained among this page's search aliases.
Why does 4T-47678/47620 list two speeds, 2,600 and 3,500 r/min?
The lower figure, 2,600 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-47678/47620 at 3,500 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.