2580-2520 bearing: complete specifications & equivalents
The 2580-2520 is a ANSI ABMA 19.2 radial bearing sized 31.75 x 66.421 x 25.4 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | NTN |
| Bore diameter d | 31.75 mm |
| Outer diameter D | 66.421 mm |
| Width B | 25.4 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | steel |
| Basic dynamic load rating C | 76.5 kN |
| Basic static load rating C0 | 81.5 kN |
| Limiting speed (mechanical) | 5700 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 410 g |
| Manufacturer designation | NTN 4T-2580/2520 |
| 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 | 1.25 in |
|---|---|
| Outer diameter D | 2.615 in |
| Width B | 1 in |
| ISO bore code | — |
| Radial section height (D−d)/2 | 17.3 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) | 32 of 148 |
| Bore above smallest 4t-inch-series size | 19.05 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| 2580-2523 | NTN | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same NTN cone 4T-2580 paired with a different cup (2523): cone interchangeable, cup differs — OD, assembled width T and ratings follow the cup. Verify the full cone/cup reference 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 2580-2520 model number is decoded
The NTN 2203E inch table prints 4T-2580/2520 at 31.75 mm bore (1.25 in), 66.421 mm cup OD and 25.4 mm assembled T, with a grease limiting speed of 5,700 r/min and an oil ceiling of 7,600 r/min. Cone and cup of 4T-2580/2520 are separately stocked parts: a worn 2520 cup can be replaced against the existing 2580 cone, provided the new cup carries the identical reference — pairing across references changes the 25.4 mm assembled width and the rating. Imperial cross-check for the drawing: 31.75×66.421×25.4 mm converts to 1.25 × 2.615 × 1 in; the ABMA envelope swaps with like-numbered inch parts but the 76.5/81.5 kN ratings are NTN-specific. Housing fitment sequence for 4T-2580/2520: press the 2520 cup square into the 66.421 mm seat first, then bring the 2580 cone (on its 31.75 mm shaft) into adjustment — the two references are separate engineering parts that happen to ship as one set. NTN grades inch 4T bearings as open bearings without integral seals; at 31.75 mm bore the application supplies sealing and the grease fill or oil feed.
Typical equipment & failure modes
Common applications
- construction-equipment pivot and wheel positions
- mining and quarry conveyor drive pulleys
- machine-tool headstocks on inch spindles
- pump and blower drive shafts with combined load
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
- edge loading when shaft deflection exceeds the few arc-minutes an adjusted pair tolerates
Selection pitfalls — read before you substitute
- Hub and pinion positions of this 31.75 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-2580/2520.
- The pure-numeric inch family at 31.75 mm bore (66.421×25.4 mm assembled) is one of several inch families sharing similar bores; cross-series swaps change OD, T and contact angle, so match the full 2580/2520 reference at purchase.
- Do not confuse T (25.4 mm, the assembled cone-plus-cup width) with the cone width when drawing spacers; an abutment sized to T leaves the cup unseated.
- Open 4T-2580/2520 sets have no seals: a hub or gearbox needs external sealing or the 5,700 r/min grease figure is meaningless once water reaches the cone rib.
- Fit selection follows the rotating ring: a rotating cone on a 31.75 mm shaft takes a k5/m5 seat, and a rotating cup reverses the logic — decide from the load diagram, not from habit.
- The 76.5/81.5 kN ratings here are NTN Ball and Roller Bearings CAT.No.2203E figures for 4T-2580/2520; 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-2580/2520?
4T-2580/2520 is an inch-series single-row tapered roller bearing to the ABMA boundary plan: 31.75 mm bore (1.25 in), 66.421 mm outside diameter and 25.4 mm assembled width T (2.615 × 1 in). From NTN Ball and Roller Bearings CAT.No.2203E: C 76.5 kN, C0 81.5 kN, grease limiting speed 5,700 r/min, oil speed 7,600 r/min, mass about 410 g. It is an open, separable cone/cup set with a pressed-steel cage.
Are the cone and cup of 4T-2580/2520 interchangeable separately?
Yes — ABMA inch parts are individually interchangeable: the 2580 cone or the 2520 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 76.5/81.5 kN ratings change with the cup.
What is the difference between 4T-2580/2520 and a metric ISO 355 tapered bearing?
4T-2580/2520 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 31.75×66.421×25.4 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-2580/2520 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 2580/2520 references; the 4T spelling is retained among this page's search aliases.
Why does 4T-2580/2520 list two speeds, 5,700 and 7,600 r/min?
The lower figure, 5,700 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-2580/2520 at 7,600 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.