31593-31520 bearing: complete specifications & equivalents
The 31593-31520 is a ANSI ABMA 19.2 radial bearing sized 34.925 x 76.2 x 29.37 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | NTN |
| Bore diameter d | 34.925 mm |
| Outer diameter D | 76.2 mm |
| Width B | 29.37 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | steel |
| Basic dynamic load rating C | 89.5 kN |
| Basic static load rating C0 | 97 kN |
| Limiting speed (mechanical) | 5100 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 626 g |
| Manufacturer designation | NTN 4T-31593/31520 |
| 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 | 1.375 in |
|---|---|
| Outer diameter D | 3 in |
| Width B | 1.156 in |
| ISO bore code | — |
| Radial section height (D−d)/2 | 20.6 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) | 34 of 148 |
| Bore above smallest 4t-inch-series size | 22.224999999999998 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| 31593 | 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 31593-31520 model number is decoded
NTN supplies this 1.375 in (34.925 mm) shaft position as 4T-31593/31520: cone 31593, cup 31520, profiled rollers and a pressed-steel cage, rated 89.5 kN basic dynamic and 97 kN static. Unlike ISO 355 metric numbers, this ABMA code does not encode the bore arithmetically: 31593 identifies the cone of 34.925 mm (1.375 in) bore by catalogue lookup, and 31520 fixes the 76.2 mm OD. The 20.6 mm radial section over the 34.925 mm bore positions the contact line of the pair; abutment shoulders and spacers are dimensioned from that geometry, not from the bore alone. Cup-side note for 31520: within the pure-numeric inch family tables the 31593 cone is listed against several cup options, and it is the cup that fixes the 76.2 mm OD and the 29.37 mm assembled width — quote the full 31593/31520 pair, never the cone alone. Contact-pattern check with marking blue: a pattern biased to one roller end means the 34.925 mm pair is misadjusted and the set will edge-load in service.
Typical equipment & failure modes
Common applications
- mining and quarry conveyor drive pulleys
- machine-tool headstocks on inch spindles
- pump and blower drive shafts with combined load
- truck and trailer axle hubs on inch-dimensioned axles
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
- cage fatigue when the pair runs continuously near the grease limiting speed without oil cooling
- brinell marks on cone and cup raceways from impact during handling or hammer fitting
Selection pitfalls — read before you substitute
- Hub and pinion positions of this 34.925 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-31593/31520.
- The pure-numeric inch family at 34.925 mm bore (76.2×29.37 mm assembled) is one of several inch families sharing similar bores; cross-series swaps change OD, T and contact angle, so match the full 31593/31520 reference at purchase.
- ABMA makes the 34.925×76.2 mm envelope interchangeable, not the ratings: NTN prints 89.5/97 kN for this execution and another make of the same number can differ in roller complement.
- Replacing one half of an adjusted pair without resetting end play negates the 29.37 mm T logic: re-adjust the set and re-verify the contact pattern rather than reusing the old spacer stack.
- Quote the full 31593/31520 pair at ordering: the 31593 cone also ships against sibling cups, and a cup from another reference changes the 29.37 mm assembled width and the rating.
- The 89.5/97 kN ratings here are NTN Ball and Roller Bearings CAT.No.2203E figures for 4T-31593/31520; 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-31593/31520?
4T-31593/31520 is an inch-series single-row tapered roller bearing to the ABMA boundary plan: 34.925 mm bore (1.375 in), 76.2 mm outside diameter and 29.37 mm assembled width T (3 × 1.156 in). From NTN Ball and Roller Bearings CAT.No.2203E: C 89.5 kN, C0 97 kN, grease limiting speed 5,100 r/min, oil speed 6,800 r/min, mass about 626 g. It is an open, separable cone/cup set with a pressed-steel cage.
Are the cone and cup of 4T-31593/31520 interchangeable separately?
Yes — ABMA inch parts are individually interchangeable: the 31593 cone or the 31520 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 89.5/97 kN ratings change with the cup.
What is the difference between 4T-31593/31520 and a metric ISO 355 tapered bearing?
4T-31593/31520 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 34.925×76.2×29.37 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-31593/31520 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 31593/31520 references; the 4T spelling is retained among this page's search aliases.
Why does 4T-31593/31520 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-31593/31520 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.