2585-2523 bearing: complete specifications & equivalents
The 2585-2523 is a ANSI ABMA 19.2 radial bearing sized 33.338 x 69.85 x 23.812 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | NTN |
| Bore diameter d | 33.338 mm |
| Outer diameter D | 69.85 mm |
| Width B | 23.812 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 | 436 g |
| Manufacturer designation | NTN 4T-2585/2523 |
| 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 | 1.313 in |
|---|---|
| Outer diameter D | 2.75 in |
| Width B | 0.937 in |
| ISO bore code | — |
| Radial section height (D−d)/2 | 18.3 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) | 33 of 148 |
| Bore above smallest 4t-inch-series size | 20.638 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| 2585 | 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 2585-2523 model number is decoded
4T-2585/2523 is the NTN 4T catalogue entry for a 33.338×69.85×23.812 mm inch tapered roller bearing — an ABMA-dimensioned cone/cup set, not an ISO 355 metric bearing, even though the table quotes metric equivalents. The 4T prefix is NTN's tapered roller quality mark stamped on both parts; it is a brand mark, not a size code, so cross-references quote 2585/2523 without it. Grease relubrication at the 5,700 r/min limiting speed targets the cone-rib contact; sustaining 7,600 r/min needs an oil supply directed at the large roller ends. Cup-side note for 2523: within the pure-numeric inch family tables the 2585 cone is listed against several cup options, and it is the cup that fixes the 69.85 mm OD and the 23.812 mm assembled width — quote the full 2585/2523 pair, never the cone alone. Minimum load matters at speed: an unloaded 4T-2585/2523 run near 5,700 r/min lets the rollers skid; lightly spring-preload high-speed pair arrangements.
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
- cup creep and housing fretting when the cup seat is cut too loose for the rotating load
- flaking on one cone only when a bent shaft loads the O/X pair unevenly
- 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 33.338 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-2585/2523.
- The pure-numeric inch family at 33.338 mm bore (69.85×23.812 mm assembled) is one of several inch families sharing similar bores; cross-series swaps change OD, T and contact angle, so match the full 2585/2523 reference at purchase.
- Open 4T-2585/2523 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.
- Grease packs must leave free volume inside the 23.812 mm-wide set; over-greasing a pair churning near the oil-band speed of 7,600 r/min raises temperature and destroys the setting.
- An unloaded 4T-2585/2523 near 5,700 r/min lets rollers skid and smear the cone rib; spring-preload lightly loaded high-speed pairs.
- The 76.5/81.5 kN ratings here are NTN Ball and Roller Bearings CAT.No.2203E figures for 4T-2585/2523; 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-2585/2523?
4T-2585/2523 is an inch-series single-row tapered roller bearing to the ABMA boundary plan: 33.338 mm bore (1.313 in), 69.85 mm outside diameter and 23.812 mm assembled width T (2.75 × 0.937 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 436 g. It is an open, separable cone/cup set with a pressed-steel cage.
Are the cone and cup of 4T-2585/2523 interchangeable separately?
Yes — ABMA inch parts are individually interchangeable: the 2585 cone or the 2523 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-2585/2523 and a metric ISO 355 tapered bearing?
4T-2585/2523 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 33.338×69.85×23.812 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-2585/2523 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 2585/2523 references; the 4T spelling is retained among this page's search aliases.
Why does 4T-2585/2523 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-2585/2523 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.