1985-1930 bearing: complete specifications & equivalents
The 1985-1930 is a ANSI ABMA 19.2 radial bearing sized 28.575 x 56.896 x 19.845 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | NTN |
| Bore diameter d | 28.575 mm |
| Outer diameter D | 56.896 mm |
| Width B | 19.845 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | steel |
| Basic dynamic load rating C | 45 kN |
| Basic static load rating C0 | 44.5 kN |
| Limiting speed (mechanical) | 6700 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 217 g |
| Manufacturer designation | NTN 4T-1985/1930 |
| 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 | 1.125 in |
|---|---|
| Outer diameter D | 2.24 in |
| Width B | 0.781 in |
| ISO bore code | — |
| Radial section height (D−d)/2 | 14.2 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) | 23 of 148 |
| Bore above smallest 4t-inch-series size | 15.875 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| 1985-1932 | NTN | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same NTN cone 4T-1985 paired with a different cup (1932): cone interchangeable, cup differs — OD, assembled width T and ratings follow the cup. Verify the full cone/cup reference before substituting. |
| 1985-1931 | NTN | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same NTN cone 4T-1985 paired with a different cup (1931): cone interchangeable, cup differs — OD, assembled width T and ratings follow the cup. Verify the full cone/cup reference before substituting. |
| 1985-1922 | SKF | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 28.575×56.896×19.845 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 1985-1930 model number is decoded
For an inch shaft of 28.575 mm carrying combined radial and thrust load, NTN lists 4T-1985/1930, a single-row 4T tapered roller set of 45 kN C and 44.5 kN C0 inside the 56.896 mm OD cup. Cone and cup of 4T-1985/1930 are separately stocked parts: a worn 1930 cup can be replaced against the existing 1985 cone, provided the new cup carries the identical reference — pairing across references changes the 19.845 mm assembled width and the rating. Two single-row inch sets are normally mounted as an adjusted O or X pair; the 19.845 mm T of each 4T-1985/1930 enters the spacer calculation, so the tolerance on assembled width matters as much as the bore fit. The printed 45/44.5 kN ratings belong to the assembled 1985+1930 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. Back-to-back (O) and face-to-face (X) arrangements of two 4T-1985/1930 sets react differently to shaft bending; choose the orientation for the moment load before locking shoulder geometry.
Typical equipment & failure modes
Common applications
- truck and trailer axle hubs on inch-dimensioned axles
- agricultural tractor transmission and PTO shafts
- industrial gearboxes built to inch shafting
- construction-equipment pivot and wheel positions
Known failure patterns
- cone-rib and roller large-end smearing when the adjusted pair runs with preload but starved lubricant film
- 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 damage from a mounting blow transmitted through the roller complement
- indentation of the raceways by hard particles in an open, unsealed arrangement
Selection pitfalls — read before you substitute
- Hub and pinion positions of this 28.575 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-1985/1930.
- The pure-numeric inch family at 28.575 mm bore (56.896×19.845 mm assembled) is one of several inch families sharing similar bores; cross-series swaps change OD, T and contact angle, so match the full 1985/1930 reference at purchase.
- Do not confuse T (19.845 mm, the assembled cone-plus-cup width) with the cone width when drawing spacers; an abutment sized to T leaves the cup unseated.
- Shaft and housing fillets must clear the ring chamfers of 1985 and 1930; use undercut shoulders so the rings seat on the face, not on a radius.
- Do not confuse T (19.845 mm, the assembled cone-plus-cup width) with the cone width when drawing spacers; an abutment sized to T leaves the cup unseated.
- The 45/44.5 kN ratings here are NTN Ball and Roller Bearings CAT.No.2203E figures for 4T-1985/1930; 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-1985/1930?
4T-1985/1930 is an inch-series single-row tapered roller bearing to the ABMA boundary plan: 28.575 mm bore (1.125 in), 56.896 mm outside diameter and 19.845 mm assembled width T (2.24 × 0.781 in). From NTN Ball and Roller Bearings CAT.No.2203E: C 45 kN, C0 44.5 kN, grease limiting speed 6,700 r/min, oil speed 8,900 r/min, mass about 217 g. It is an open, separable cone/cup set with a pressed-steel cage.
Are the cone and cup of 4T-1985/1930 interchangeable separately?
Yes — ABMA inch parts are individually interchangeable: the 1985 cone or the 1930 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 45/44.5 kN ratings change with the cup.
What is the difference between 4T-1985/1930 and a metric ISO 355 tapered bearing?
4T-1985/1930 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 28.575×56.896×19.845 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-1985/1930 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 1985/1930 references; the 4T spelling is retained among this page's search aliases.
Why does 4T-1985/1930 list two speeds, 6,700 and 8,900 r/min?
The lower figure, 6,700 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-1985/1930 at 8,900 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.