46780-46720 bearing: complete specifications & equivalents
The 46780-46720 is a ANSI ABMA 19.2 radial bearing sized 158.75 x 225.425 x 41.275 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | NTN |
| Bore diameter d | 158.75 mm |
| Outer diameter D | 225.425 mm |
| Width B | 41.275 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | steel |
| Basic dynamic load rating C | 282 kN |
| Basic static load rating C0 | 555 kN |
| Limiting speed (mechanical) | 1400 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 5190 g |
| Manufacturer designation | NTN 4T-46780/46720 |
| 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 | 6.25 in |
|---|---|
| Outer diameter D | 8.875 in |
| Width B | 1.625 in |
| ISO bore code | — |
| Radial section height (D−d)/2 | 33.3 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) | 142 of 148 |
| Bore above smallest 4t-inch-series size | 146.05 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| 46780 | 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 46780-46720 model number is decoded
4T-46780/46720 is the NTN 4T catalogue entry for a 158.75×225.425×41.275 mm inch tapered roller bearing — an ABMA-dimensioned cone/cup set, not an ISO 355 metric bearing, even though the table quotes metric equivalents. Unlike ISO 355 metric numbers, this ABMA code does not encode the bore arithmetically: 46780 identifies the cone of 158.75 mm (6.25 in) bore by catalogue lookup, and 46720 fixes the 225.425 mm OD. Selection: C 282 kN against C0 555 kN gives a C0/C ratio of 1.97 for the 158.75 mm bore; the pair is counted as one adjusted unit when checking L10 at the equivalent combined load. Housing fitment sequence for 4T-46780/46720: press the 46720 cup square into the 225.425 mm seat first, then bring the 46780 cone (on its 158.75 mm shaft) into adjustment — the two references are separate engineering parts that happen to ship as one set. The rollers run with their large ends against the cone's guide rib; lubricant must reach that rib face of 4T-46780/46720, not only the raceway, or the pair smears on the first overloaded start.
Typical equipment & failure modes
Common applications
- large shredder and recycler main shafts
- power-plant coal-mill and fan shafts
- rolling-mill pinion stands and roll-neck auxiliaries
- mine hoist and dragline drum shafts
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
- cage fatigue when the pair runs continuously near the grease limiting speed without oil cooling
- edge loading when shaft deflection exceeds the few arc-minutes an adjusted pair tolerates
Selection pitfalls — read before you substitute
- At 158.75 mm bore the 4T-46780/46720 set is adjusted with hydraulic nuts or measured shims on mill and crane positions; manual torque methods cannot control preload at the 282 kN C level.
- The pure-numeric inch family at 158.75 mm bore (225.425×41.275 mm assembled) is one of several inch families sharing similar bores; cross-series swaps change OD, T and contact angle, so match the full 46780/46720 reference at purchase.
- Grease packs must leave free volume inside the 41.275 mm-wide set; over-greasing a pair churning near the oil-band speed of 1,900 r/min raises temperature and destroys the setting.
- Shaft and housing fillets must clear the ring chamfers of 46780 and 46720; use undercut shoulders so the rings seat on the face, not on a radius.
- Quote the full 46780/46720 pair at ordering: the 46780 cone also ships against sibling cups, and a cup from another reference changes the 41.275 mm assembled width and the rating.
- The 282/555 kN ratings here are NTN Ball and Roller Bearings CAT.No.2203E figures for 4T-46780/46720; 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-46780/46720?
4T-46780/46720 is an inch-series single-row tapered roller bearing to the ABMA boundary plan: 158.75 mm bore (6.25 in), 225.425 mm outside diameter and 41.275 mm assembled width T (8.875 × 1.625 in). From NTN Ball and Roller Bearings CAT.No.2203E: C 282 kN, C0 555 kN, grease limiting speed 1,400 r/min, oil speed 1,900 r/min, mass about 5190 g. It is an open, separable cone/cup set with a pressed-steel cage.
Are the cone and cup of 4T-46780/46720 interchangeable separately?
Yes — ABMA inch parts are individually interchangeable: the 46780 cone or the 46720 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 282/555 kN ratings change with the cup.
What is the difference between 4T-46780/46720 and a metric ISO 355 tapered bearing?
4T-46780/46720 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 158.75×225.425×41.275 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-46780/46720 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 46780/46720 references; the 4T spelling is retained among this page's search aliases.
Why does 4T-46780/46720 list two speeds, 1,400 and 1,900 r/min?
The lower figure, 1,400 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-46780/46720 at 1,900 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.