24780-24720-NTN bearing: complete specifications & equivalents
The 24780-24720-NTN is a ANSI ABMA 19.2 radial bearing sized 41.275 x 76.2 x 22.225 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | NTN |
| Bore diameter d | 41.275 mm |
| Outer diameter D | 76.2 mm |
| Width B | 22.225 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | steel |
| Basic dynamic load rating C | 72 kN |
| Basic static load rating C0 | 80.5 kN |
| Limiting speed (mechanical) | 4900 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 435 g |
| Manufacturer designation | NTN 4T-24780/24720 |
| 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 | 1.625 in |
|---|---|
| Outer diameter D | 3 in |
| Width B | 0.875 in |
| ISO bore code | — |
| Radial section height (D−d)/2 | 17.5 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) | 47 of 148 |
| Bore above smallest 4t-inch-series size | 28.575 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| 24780-24720 | SKF | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 41.275×76.2×22.225 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 24780-24720-NTN model number is decoded
The NTN 2203E inch table prints 4T-24780/24720 at 41.275 mm bore (1.625 in), 76.2 mm cup OD and 22.225 mm assembled T, with a grease limiting speed of 4,900 r/min and an oil ceiling of 6,500 r/min. Unlike ISO 355 metric numbers, this ABMA code does not encode the bore arithmetically: 24780 identifies the cone of 41.275 mm (1.625 in) bore by catalogue lookup, and 24720 fixes the 76.2 mm OD. The 1.7 kN of dynamic capacity per millimetre of bore summarises the 72 kN rating over the 41.275 mm bore — sanity-check any interchange candidate against this ratio and the 22.225 mm T. Housing fitment sequence for 4T-24780/24720: press the 24720 cup square into the 76.2 mm seat first, then bring the 24780 cone (on its 41.275 mm shaft) into adjustment — the two references are separate engineering parts that happen to ship as one set. Contact-pattern check with marking blue: a pattern biased to one roller end means the 41.275 mm pair is misadjusted and the set will edge-load in service.
Typical equipment & failure modes
Common applications
- agricultural tractor transmission and PTO shafts
- industrial gearboxes built to inch shafting
- construction-equipment pivot and wheel positions
- mining and quarry conveyor drive pulleys
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
- pressed-steel cage pocket wear from roller skid at light radial load and high speed
- fretting corrosion on a loose cone seat that creeps under rotating load
Selection pitfalls — read before you substitute
- Hub and pinion positions of this 41.275 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-24780/24720.
- The pure-numeric inch family at 41.275 mm bore (76.2×22.225 mm assembled) is one of several inch families sharing similar bores; cross-series swaps change OD, T and contact angle, so match the full 24780/24720 reference at purchase.
- Open 4T-24780/24720 sets have no seals: a hub or gearbox needs external sealing or the 4,900 r/min grease figure is meaningless once water reaches the cone rib.
- Shaft and housing fillets must clear the ring chamfers of 24780 and 24720; use undercut shoulders so the rings seat on the face, not on a radius.
- Shaft and housing fillets must clear the ring chamfers of 24780 and 24720; use undercut shoulders so the rings seat on the face, not on a radius.
- The 72/80.5 kN ratings here are NTN Ball and Roller Bearings CAT.No.2203E figures for 4T-24780/24720; 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-24780/24720?
4T-24780/24720 is an inch-series single-row tapered roller bearing to the ABMA boundary plan: 41.275 mm bore (1.625 in), 76.2 mm outside diameter and 22.225 mm assembled width T (3 × 0.875 in). From NTN Ball and Roller Bearings CAT.No.2203E: C 72 kN, C0 80.5 kN, grease limiting speed 4,900 r/min, oil speed 6,500 r/min, mass about 435 g. It is an open, separable cone/cup set with a pressed-steel cage.
Are the cone and cup of 4T-24780/24720 interchangeable separately?
Yes — ABMA inch parts are individually interchangeable: the 24780 cone or the 24720 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 72/80.5 kN ratings change with the cup.
What is the difference between 4T-24780/24720 and a metric ISO 355 tapered bearing?
4T-24780/24720 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 41.275×76.2×22.225 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-24780/24720 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 24780/24720 references; the 4T spelling is retained among this page's search aliases.
Why does 4T-24780/24720 list two speeds, 4,900 and 6,500 r/min?
The lower figure, 4,900 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-24780/24720 at 6,500 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.