02878-02820 bearing: complete specifications & equivalents
The 02878-02820 is a ANSI ABMA 19.2 radial bearing sized 34.925 x 73.025 x 22.225 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | NTN |
| Bore diameter d | 34.925 mm |
| Outer diameter D | 73.025 mm |
| Width B | 22.225 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | steel |
| Basic dynamic load rating C | 62.5 kN |
| Basic static load rating C0 | 68 kN |
| Limiting speed (mechanical) | 5300 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 426 g |
| Manufacturer designation | NTN 4T-02878/02820 |
| 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 | 1.375 in |
|---|---|
| Outer diameter D | 2.875 in |
| Width B | 0.875 in |
| ISO bore code | — |
| Radial section height (D−d)/2 | 19.1 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) | 34 of 148 |
| Bore above smallest 4t-inch-series size | 22.224999999999998 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| 02878 | ISO 15 | full Dimensions and internal design equivalent — standard interchange. | ISO 15 boundary-dimension envelope; brand-specific OEM equivalents (NSK/FAG/NTN) pending multi-source data. |
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 02878-02820 model number is decoded
For an inch shaft of 34.925 mm carrying combined radial and thrust load, NTN lists 4T-02878/02820, a single-row 4T tapered roller set of 62.5 kN C and 68 kN C0 inside the 73.025 mm OD cup. Unlike ISO 355 metric numbers, this ABMA code does not encode the bore arithmetically: 02878 identifies the cone of 34.925 mm (1.375 in) bore by catalogue lookup, and 02820 fixes the 73.025 mm OD. The 19.1 mm radial section over the 34.925 mm bore positions the contact line of the pair; abutment shoulders and spacers are dimensioned from that geometry, not from the bore alone. Cup-side note for 02820: within the pure-numeric inch family tables the 02878 cone is listed against several cup options, and it is the cup that fixes the 73.025 mm OD and the 22.225 mm assembled width — quote the full 02878/02820 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-02878/02820, not only the raceway, or the pair smears on the first overloaded start.
Typical equipment & failure modes
Common applications
- agricultural tractor transmission and PTO shafts
- industrial gearboxes built to inch shafting
- construction-equipment pivot and wheel positions
- mining and quarry conveyor drive pulleys
Known failure patterns
- cone-rib and roller large-end smearing when the adjusted pair runs with preload but starved lubricant film
- 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 fatigue when the pair runs continuously near the grease limiting speed without oil cooling
- rolling-contact fatigue spalling after the catalogue L10 life at the actual combined load
Selection pitfalls — read before you substitute
- Hub and pinion positions of this 34.925 mm class are adjusted in pairs; verify end play against the axle or gearbox drawing and re-torque after bedding-in instead of trusting the first setting on 4T-02878/02820.
- The pure-numeric inch family at 34.925 mm bore (73.025×22.225 mm assembled) is one of several inch families sharing similar bores; cross-series swaps change OD, T and contact angle, so match the full 02878/02820 reference at purchase.
- An unloaded 4T-02878/02820 near 5,300 r/min lets rollers skid and smear the cone rib; spring-preload lightly loaded high-speed pairs.
- Inch and metric bores collide on paper — 34.925 mm is 1.375 in, not a round metric size; a metric bearing that seems 0.1 mm off will not seat on the inch shaft.
- Shaft and housing fillets must clear the ring chamfers of 02878 and 02820; use undercut shoulders so the rings seat on the face, not on a radius.
- The 62.5/68 kN ratings here are NTN Ball and Roller Bearings CAT.No.2203E figures for 4T-02878/02820; 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-02878/02820?
4T-02878/02820 is an inch-series single-row tapered roller bearing to the ABMA boundary plan: 34.925 mm bore (1.375 in), 73.025 mm outside diameter and 22.225 mm assembled width T (2.875 × 0.875 in). From NTN Ball and Roller Bearings CAT.No.2203E: C 62.5 kN, C0 68 kN, grease limiting speed 5,300 r/min, oil speed 7,000 r/min, mass about 426 g. It is an open, separable cone/cup set with a pressed-steel cage.
Are the cone and cup of 4T-02878/02820 interchangeable separately?
Yes — ABMA inch parts are individually interchangeable: the 02878 cone or the 02820 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 62.5/68 kN ratings change with the cup.
What is the difference between 4T-02878/02820 and a metric ISO 355 tapered bearing?
4T-02878/02820 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 34.925×73.025×22.225 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-02878/02820 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 02878/02820 references; the 4T spelling is retained among this page's search aliases.
Why does 4T-02878/02820 list two speeds, 5,300 and 7,000 r/min?
The lower figure, 5,300 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-02878/02820 at 7,000 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.