1985-1931 bearing: complete specifications & equivalents
The 1985-1931 is a ANSI ABMA 19.2 radial bearing sized 28.575 x 60.325 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 | 60.325 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 | 256 g |
| Manufacturer designation | NTN 4T-1985/1931 |
| 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 | 2.375 in |
| Width B | 0.781 in |
| ISO bore code | — |
| Radial section height (D−d)/2 | 15.9 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 |
|---|---|---|---|
| 1985-1930 | NTN | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same NTN cone 4T-1985 paired with a different cup (1930): cone interchangeable, cup differs — OD, assembled width T and ratings follow the cup. Verify the full cone/cup reference before substituting. |
| 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. |
| 1985-1922 | SKF | verify Commonly quoted cross reference; confirm against the target catalog before ordering. | Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue. |
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 1985-1931 model number is decoded
4T-1985/1931 belongs to the NTN inch 4T tapered roller range (pure-numeric inch family); cone and cup are ordered by their own references and are individually interchangeable with like-numbered parts. Unlike ISO 355 metric numbers, this ABMA code does not encode the bore arithmetically: 1985 identifies the cone of 28.575 mm (1.125 in) bore by catalogue lookup, and 1931 fixes the 60.325 mm OD. Imperial cross-check for the drawing: 28.575×60.325×19.845 mm converts to 1.125 × 2.375 × 0.781 in; the ABMA envelope swaps with like-numbered inch parts but the 45/44.5 kN ratings are NTN-specific. The printed 45/44.5 kN ratings belong to the assembled 1985+1931 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. After bedding-in, re-check the end play of the adjusted 4T-1985/1931 pair — initial seating of the ring faces relaxes the setting slightly.
Typical equipment & failure modes
Common applications
- industrial gearboxes built to inch shafting
- construction-equipment pivot and wheel positions
- mining and quarry conveyor drive pulleys
- machine-tool headstocks on inch spindles
Known failure patterns
- rib-face scoring when the thrust share of the combined load exceeds what the cone rib of this size carries
- 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
- pressed-steel cage pocket wear from roller skid at light radial load and high speed
- 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-1985/1931.
- The pure-numeric inch family at 28.575 mm bore (60.325×19.845 mm assembled) is one of several inch families sharing similar bores; cross-series swaps change OD, T and contact angle, so match the full 1985/1931 reference at purchase.
- Replacing one half of an adjusted pair without resetting end play negates the 19.845 mm T logic: re-adjust the set and re-verify the contact pattern rather than reusing the old spacer stack.
- Fit selection follows the rotating ring: a rotating cone on a 28.575 mm shaft takes a k5/m5 seat, and a rotating cup reverses the logic — decide from the load diagram, not from habit.
- Quote the full 1985/1931 pair at ordering: the 1985 cone also ships against sibling cups, and a cup from another reference changes the 19.845 mm assembled width and the rating.
- The 45/44.5 kN ratings here are NTN Ball and Roller Bearings CAT.No.2203E figures for 4T-1985/1931; 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-1985/1931?
4T-1985/1931 is an inch-series single-row tapered roller bearing to the ABMA boundary plan: 28.575 mm bore (1.125 in), 60.325 mm outside diameter and 19.845 mm assembled width T (2.375 × 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 256 g. It is an open, separable cone/cup set with a pressed-steel cage.
Are the cone and cup of 4T-1985/1931 interchangeable separately?
Yes — ABMA inch parts are individually interchangeable: the 1985 cone or the 1931 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-1985/1931 and a metric ISO 355 tapered bearing?
4T-1985/1931 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 28.575×60.325×19.845 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-1985/1931 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 1985/1931 references; the 4T spelling is retained among this page's search aliases.
Why does 4T-1985/1931 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-1985/1931 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.