2785-2720 bearing: complete specifications & equivalents
The 2785-2720 is a ANSI ABMA 19.2 radial bearing sized 33.338 x 76.2 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 | 76.2 mm |
| Width B | 23.812 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | steel |
| Basic dynamic load rating C | 81 kN |
| Basic static load rating C0 | 90.5 kN |
| Limiting speed (mechanical) | 5100 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 548 g |
| Manufacturer designation | NTN 4T-2785/2720 |
| 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 | 3 in |
| Width B | 0.937 in |
| ISO bore code | — |
| Radial section height (D−d)/2 | 21.4 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 |
|---|---|---|---|
| 2785 | 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 2785-2720 model number is decoded
In NTN Ball and Roller Bearings CAT.No.2203E, the order number 4T-2785/2720 denotes the pure-numeric inch family of NTN inch tapered roller bearings — cone 2785 and cup 2720 delivered as a matched, separable pair of 33.338 mm bore and 76.2 mm outside diameter. Reading the designation: 4T-2785/2720 follows the ABMA inch convention — the number before the slash is the cone (inner ring with roller set and cage), the number after the slash is the cup (outer ring), and the pure-numeric inch family lettering ties the pair to its boundary plan. The 2.4 kN of dynamic capacity per millimetre of bore summarises the 81 kN rating over the 33.338 mm bore — sanity-check any interchange candidate against this ratio and the 23.812 mm T. Cup-side note for 2720: within the pure-numeric inch family tables the 2785 cone is listed against several cup options, and it is the cup that fixes the 76.2 mm OD and the 23.812 mm assembled width — quote the full 2785/2720 pair, never the cone alone. Back-to-back (O) and face-to-face (X) arrangements of two 4T-2785/2720 sets react differently to shaft bending; choose the orientation for the moment load before locking shoulder geometry.
Typical equipment & failure modes
Common applications
- pump and blower drive shafts with combined load
- truck and trailer axle hubs on inch-dimensioned axles
- agricultural tractor transmission and PTO shafts
- industrial gearboxes built to inch shafting
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 damage from a mounting blow transmitted through the roller complement
- 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-2785/2720.
- The pure-numeric inch family at 33.338 mm bore (76.2×23.812 mm assembled) is one of several inch families sharing similar bores; cross-series swaps change OD, T and contact angle, so match the full 2785/2720 reference at purchase.
- Never drive the 76.2 mm cup home through the rollers: fitting force goes through the ring faces only, or brinell marks release as noise within the first running hours.
- An unloaded 4T-2785/2720 near 5,100 r/min lets rollers skid and smear the cone rib; spring-preload lightly loaded high-speed pairs.
- Shaft and housing fillets must clear the ring chamfers of 2785 and 2720; use undercut shoulders so the rings seat on the face, not on a radius.
- The 81/90.5 kN ratings here are NTN Ball and Roller Bearings CAT.No.2203E figures for 4T-2785/2720; 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-2785/2720?
4T-2785/2720 is an inch-series single-row tapered roller bearing to the ABMA boundary plan: 33.338 mm bore (1.313 in), 76.2 mm outside diameter and 23.812 mm assembled width T (3 × 0.937 in). From NTN Ball and Roller Bearings CAT.No.2203E: C 81 kN, C0 90.5 kN, grease limiting speed 5,100 r/min, oil speed 6,800 r/min, mass about 548 g. It is an open, separable cone/cup set with a pressed-steel cage.
Are the cone and cup of 4T-2785/2720 interchangeable separately?
Yes — ABMA inch parts are individually interchangeable: the 2785 cone or the 2720 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 81/90.5 kN ratings change with the cup.
What is the difference between 4T-2785/2720 and a metric ISO 355 tapered bearing?
4T-2785/2720 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 33.338×76.2×23.812 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-2785/2720 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 2785/2720 references; the 4T spelling is retained among this page's search aliases.
Why does 4T-2785/2720 list two speeds, 5,100 and 6,800 r/min?
The lower figure, 5,100 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-2785/2720 at 6,800 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.