799-792 bearing: complete specifications & equivalents
The 799-792 is a ANSI ABMA 19.2 radial bearing sized 128.588 x 206.375 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 | 128.588 mm |
| Outer diameter D | 206.375 mm |
| Width B | 47.625 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | steel |
| Basic dynamic load rating C | 350 kN |
| Basic static load rating C0 | 520 kN |
| Limiting speed (mechanical) | 1700 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 5770 g |
| Manufacturer designation | NTN 4T-799/792 |
| 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 | 5.063 in |
|---|---|
| Outer diameter D | 8.125 in |
| Width B | 1.875 in |
| ISO bore code | — |
| Radial section height (D−d)/2 | 38.9 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) | 134 of 148 |
| Bore above smallest 4t-inch-series size | 115.88799999999999 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| 799 | 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 799-792 model number is decoded
For an inch shaft of 128.588 mm carrying combined radial and thrust load, NTN lists 4T-799/792, a single-row 4T tapered roller set of 350 kN C and 520 kN C0 inside the 206.375 mm OD cup. Letter prefixes inherited from the inch convention mark the load family: LM reads as light-medium, HM as heavy-medium, LL as extra-light, J-prefixed codes as metric-envelope families — 799 sits in the pure-numeric inch family. Grease relubrication at the 1,700 r/min limiting speed targets the cone-rib contact; sustaining 2,200 r/min needs an oil supply directed at the large roller ends. Cup-side note for 792: within the pure-numeric inch family tables the 799 cone is listed against several cup options, and it is the cup that fixes the 206.375 mm OD and the 47.625 mm assembled width — quote the full 799/792 pair, never the cone alone. NTN grades inch 4T bearings as open bearings without integral seals; at 128.588 mm bore the application supplies sealing and the grease fill or oil feed.
Typical equipment & failure modes
Common applications
- mine hoist and dragline drum shafts
- heavy press and forging-machine drive shafts
- port-crane travel and hoist gearboxes
- cement-plant mill and kiln drive trains
Known failure patterns
- cone-rib and roller large-end smearing when the adjusted pair runs with preload but starved lubricant film
- flaking on one cone only when a bent shaft loads the O/X pair unevenly
- cup creep and housing fretting when the cup seat is cut too loose for the rotating load
- cage damage from a mounting blow transmitted through the roller complement
- brinell marks on cone and cup raceways from impact during handling or hammer fitting
Selection pitfalls — read before you substitute
- At 128.588 mm bore the 4T-799/792 set is adjusted with hydraulic nuts or measured shims on mill and crane positions; manual torque methods cannot control preload at the 350 kN C level.
- The pure-numeric inch family at 128.588 mm bore (206.375×47.625 mm assembled) is one of several inch families sharing similar bores; cross-series swaps change OD, T and contact angle, so match the full 799/792 reference at purchase.
- Shaft and housing fillets must clear the ring chamfers of 799 and 792; use undercut shoulders so the rings seat on the face, not on a radius.
- ABMA makes the 128.588×206.375 mm envelope interchangeable, not the ratings: NTN prints 350/520 kN for this execution and another make of the same number can differ in roller complement.
- ABMA makes the 128.588×206.375 mm envelope interchangeable, not the ratings: NTN prints 350/520 kN for this execution and another make of the same number can differ in roller complement.
- The 350/520 kN ratings here are NTN Ball and Roller Bearings CAT.No.2203E figures for 4T-799/792; 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-799/792?
4T-799/792 is an inch-series single-row tapered roller bearing to the ABMA boundary plan: 128.588 mm bore (5.063 in), 206.375 mm outside diameter and 47.625 mm assembled width T (8.125 × 1.875 in). From NTN Ball and Roller Bearings CAT.No.2203E: C 350 kN, C0 520 kN, grease limiting speed 1,700 r/min, oil speed 2,200 r/min, mass about 5770 g. It is an open, separable cone/cup set with a pressed-steel cage.
Are the cone and cup of 4T-799/792 interchangeable separately?
Yes — ABMA inch parts are individually interchangeable: the 799 cone or the 792 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 350/520 kN ratings change with the cup.
What is the difference between 4T-799/792 and a metric ISO 355 tapered bearing?
4T-799/792 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 128.588×206.375×47.625 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-799/792 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 799/792 references; the 4T spelling is retained among this page's search aliases.
Why does 4T-799/792 list two speeds, 1,700 and 2,200 r/min?
The lower figure, 1,700 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-799/792 at 2,200 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.