43131-43312 bearing: complete specifications & equivalents
The 43131-43312 is a ANSI ABMA 19.2 radial bearing sized 33.338 x 79.375 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 | 33.338 mm |
| Outer diameter D | 79.375 mm |
| Width B | 25.4 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | steel |
| Basic dynamic load rating C | 72.5 kN |
| Basic static load rating C0 | 67 kN |
| Limiting speed (mechanical) | 5200 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 568 g |
| Manufacturer designation | NTN 4T-43131/43312 |
| 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 | 3.125 in |
| Width B | 1 in |
| ISO bore code | — |
| Radial section height (D−d)/2 | 23 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 |
|---|---|---|---|
| 43131 | 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 43131-43312 model number is decoded
4T-43131/43312 is an NTN inch-series single-row tapered roller bearing: a separable cone-and-cup pair on the ABMA inch boundary plan, 33.338×79.375×25.4 mm (assembled width T), for a shaft of about 33.338 mm (1.313 in). Cone and cup of 4T-43131/43312 are separately stocked parts: a worn 43312 cup can be replaced against the existing 43131 cone, provided the new cup carries the identical reference — pairing across references changes the 25.4 mm assembled width and the rating. Grease relubrication at the 5,200 r/min limiting speed targets the cone-rib contact; sustaining 6,900 r/min needs an oil supply directed at the large roller ends. Housing fitment sequence for 4T-43131/43312: press the 43312 cup square into the 79.375 mm seat first, then bring the 43131 cone (on its 33.338 mm shaft) into adjustment — the two references are separate engineering parts that happen to ship as one set. Back-to-back (O) and face-to-face (X) arrangements of two 4T-43131/43312 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
- rib-face scoring when the thrust share of the combined load exceeds what the cone rib of this size carries
- 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
- fretting corrosion on a loose cone seat that creeps under rotating 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-43131/43312.
- The pure-numeric inch family at 33.338 mm bore (79.375×25.4 mm assembled) is one of several inch families sharing similar bores; cross-series swaps change OD, T and contact angle, so match the full 43131/43312 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.
- Replacing one half of an adjusted pair without resetting end play negates the 25.4 mm T logic: re-adjust the set and re-verify the contact pattern rather than reusing the old spacer stack.
- Replacing one half of an adjusted pair without resetting end play negates the 25.4 mm T logic: re-adjust the set and re-verify the contact pattern rather than reusing the old spacer stack.
- The 72.5/67 kN ratings here are NTN Ball and Roller Bearings CAT.No.2203E figures for 4T-43131/43312; 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-43131/43312?
4T-43131/43312 is an inch-series single-row tapered roller bearing to the ABMA boundary plan: 33.338 mm bore (1.313 in), 79.375 mm outside diameter and 25.4 mm assembled width T (3.125 × 1 in). From NTN Ball and Roller Bearings CAT.No.2203E: C 72.5 kN, C0 67 kN, grease limiting speed 5,200 r/min, oil speed 6,900 r/min, mass about 568 g. It is an open, separable cone/cup set with a pressed-steel cage.
Are the cone and cup of 4T-43131/43312 interchangeable separately?
Yes — ABMA inch parts are individually interchangeable: the 43131 cone or the 43312 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 72.5/67 kN ratings change with the cup.
What is the difference between 4T-43131/43312 and a metric ISO 355 tapered bearing?
4T-43131/43312 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 33.338×79.375×25.4 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-43131/43312 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 43131/43312 references; the 4T spelling is retained among this page's search aliases.
Why does 4T-43131/43312 list two speeds, 5,200 and 6,900 r/min?
The lower figure, 5,200 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-43131/43312 at 6,900 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.