15125-15245 bearing: complete specifications & equivalents
The 15125-15245 is a ANSI ABMA 19.2 radial bearing sized 31.75 x 62 x 19.05 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | NTN |
| Bore diameter d | 31.75 mm |
| Outer diameter D | 62 mm |
| Width B | 19.05 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | steel |
| Basic dynamic load rating C | 52 kN |
| Basic static load rating C0 | 54 kN |
| Limiting speed (mechanical) | 6100 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 254 g |
| Manufacturer designation | NTN 4T-15125/15245 |
| 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 | 1.25 in |
|---|---|
| Outer diameter D | 2.441 in |
| Width B | 0.75 in |
| ISO bore code | — |
| Radial section height (D−d)/2 | 15.1 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) | 32 of 148 |
| Bore above smallest 4t-inch-series size | 19.05 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| 15125 | 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 15125-15245 model number is decoded
In NTN Ball and Roller Bearings CAT.No.2203E, the order number 4T-15125/15245 denotes the pure-numeric inch family of NTN inch tapered roller bearings — cone 15125 and cup 15245 delivered as a matched, separable pair of 31.75 mm bore and 62 mm outside diameter. The 4T prefix is NTN's tapered roller quality mark stamped on both parts; it is a brand mark, not a size code, so cross-references quote 15125/15245 without it. The 15.1 mm radial section over the 31.75 mm bore positions the contact line of the pair; abutment shoulders and spacers are dimensioned from that geometry, not from the bore alone. The printed 52/54 kN ratings belong to the assembled 15125+15245 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-15125/15245 sets react differently to shaft bending; choose the orientation for the moment load before locking shoulder geometry.
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
- 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 31.75 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-15125/15245.
- The pure-numeric inch family at 31.75 mm bore (62×19.05 mm assembled) is one of several inch families sharing similar bores; cross-series swaps change OD, T and contact angle, so match the full 15125/15245 reference at purchase.
- Inch and metric bores collide on paper — 31.75 mm is 1.25 in, not a round metric size; a metric bearing that seems 0.1 mm off will not seat on the inch shaft.
- Grease packs must leave free volume inside the 19.05 mm-wide set; over-greasing a pair churning near the oil-band speed of 8,200 r/min raises temperature and destroys the setting.
- Inch and metric bores collide on paper — 31.75 mm is 1.25 in, not a round metric size; a metric bearing that seems 0.1 mm off will not seat on the inch shaft.
- The 52/54 kN ratings here are NTN Ball and Roller Bearings CAT.No.2203E figures for 4T-15125/15245; 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-15125/15245?
4T-15125/15245 is an inch-series single-row tapered roller bearing to the ABMA boundary plan: 31.75 mm bore (1.25 in), 62 mm outside diameter and 19.05 mm assembled width T (2.441 × 0.75 in). From NTN Ball and Roller Bearings CAT.No.2203E: C 52 kN, C0 54 kN, grease limiting speed 6,100 r/min, oil speed 8,200 r/min, mass about 254 g. It is an open, separable cone/cup set with a pressed-steel cage.
Are the cone and cup of 4T-15125/15245 interchangeable separately?
Yes — ABMA inch parts are individually interchangeable: the 15125 cone or the 15245 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 52/54 kN ratings change with the cup.
What is the difference between 4T-15125/15245 and a metric ISO 355 tapered bearing?
4T-15125/15245 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 31.75×62×19.05 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-15125/15245 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 15125/15245 references; the 4T spelling is retained among this page's search aliases.
Why does 4T-15125/15245 list two speeds, 6,100 and 8,200 r/min?
The lower figure, 6,100 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-15125/15245 at 8,200 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.