67790-67720 bearing: complete specifications & equivalents
The 67790-67720 is a ANSI ABMA 19.2 radial bearing sized 177.8 x 247.65 x 47.625 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | NTN |
| Bore diameter d | 177.8 mm |
| Outer diameter D | 247.65 mm |
| Width B | 47.625 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | steel |
| Basic dynamic load rating C | 380 kN |
| Basic static load rating C0 | 690 kN |
| Limiting speed (mechanical) | 1300 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 6720 g |
| Manufacturer designation | NTN 4T-67790/67720 |
| 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 | 7 in |
|---|---|
| Outer diameter D | 9.75 in |
| Width B | 1.875 in |
| ISO bore code | — |
| Radial section height (D−d)/2 | 34.9 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) | 145 of 148 |
| Bore above smallest 4t-inch-series size | 165.10000000000002 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| 67790 | 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 67790-67720 model number is decoded
The NTN 2203E inch table prints 4T-67790/67720 at 177.8 mm bore (7 in), 247.65 mm cup OD and 47.625 mm assembled T, with a grease limiting speed of 1,300 r/min and an oil ceiling of 1,700 r/min. Reading the designation: 4T-67790/67720 follows the ABMA inch convention — the number before the slash is the cone (inner ring with roller set and cage), the number after the slash is the cup (outer ring), and the pure-numeric inch family lettering ties the pair to its boundary plan. Two single-row inch sets are normally mounted as an adjusted O or X pair; the 47.625 mm T of each 4T-67790/67720 enters the spacer calculation, so the tolerance on assembled width matters as much as the bore fit. Housing fitment sequence for 4T-67790/67720: press the 67720 cup square into the 247.65 mm seat first, then bring the 67790 cone (on its 177.8 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-67790/67720 sets react differently to shaft bending; choose the orientation for the moment load before locking shoulder geometry.
Typical equipment & failure modes
Common applications
- port-crane travel and hoist gearboxes
- cement-plant mill and kiln drive trains
- large shredder and recycler main shafts
- power-plant coal-mill and fan shafts
Known failure patterns
- cone-rib and roller large-end smearing when the adjusted pair runs with preload but starved lubricant film
- 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 damage from a mounting blow transmitted through the roller complement
- edge loading when shaft deflection exceeds the few arc-minutes an adjusted pair tolerates
Selection pitfalls — read before you substitute
- At 177.8 mm bore the 4T-67790/67720 set is adjusted with hydraulic nuts or measured shims on mill and crane positions; manual torque methods cannot control preload at the 380 kN C level.
- The pure-numeric inch family at 177.8 mm bore (247.65×47.625 mm assembled) is one of several inch families sharing similar bores; cross-series swaps change OD, T and contact angle, so match the full 67790/67720 reference at purchase.
- Never drive the 247.65 mm cup home through the rollers: fitting force goes through the ring faces only, or brinell marks release as noise within the first running hours.
- Grease packs must leave free volume inside the 47.625 mm-wide set; over-greasing a pair churning near the oil-band speed of 1,700 r/min raises temperature and destroys the setting.
- Inch and metric bores collide on paper — 177.8 mm is 7 in, not a round metric size; a metric bearing that seems 0.1 mm off will not seat on the inch shaft.
- The 380/690 kN ratings here are NTN Ball and Roller Bearings CAT.No.2203E figures for 4T-67790/67720; 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-67790/67720?
4T-67790/67720 is an inch-series single-row tapered roller bearing to the ABMA boundary plan: 177.8 mm bore (7 in), 247.65 mm outside diameter and 47.625 mm assembled width T (9.75 × 1.875 in). From NTN Ball and Roller Bearings CAT.No.2203E: C 380 kN, C0 690 kN, grease limiting speed 1,300 r/min, oil speed 1,700 r/min, mass about 6720 g. It is an open, separable cone/cup set with a pressed-steel cage.
Are the cone and cup of 4T-67790/67720 interchangeable separately?
Yes — ABMA inch parts are individually interchangeable: the 67790 cone or the 67720 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 380/690 kN ratings change with the cup.
What is the difference between 4T-67790/67720 and a metric ISO 355 tapered bearing?
4T-67790/67720 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 177.8×247.65×47.625 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-67790/67720 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 67790/67720 references; the 4T spelling is retained among this page's search aliases.
Why does 4T-67790/67720 list two speeds, 1,300 and 1,700 r/min?
The lower figure, 1,300 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-67790/67720 at 1,700 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.