36990-36920-NTN bearing: complete specifications & equivalents
The 36990-36920-NTN is a ANSI ABMA 19.2 radial bearing sized 177.8 x 227.012 x 30.162 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 | 227.012 mm |
| Width B | 30.162 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | steel |
| Basic dynamic load rating C | 201 kN |
| Basic static load rating C0 | 415 kN |
| Limiting speed (mechanical) | 1300 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 2910 g |
| Manufacturer designation | NTN 4T-36990/36920 |
| 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 | 8.937 in |
| Width B | 1.187 in |
| ISO bore code | — |
| Radial section height (D−d)/2 | 24.6 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 |
|---|---|---|---|
| 36990-36920 | SKF | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 177.8×227.012×30.162 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 36990-36920-NTN model number is decoded
4T-36990/36920 is the NTN 4T catalogue entry for a 177.8×227.012×30.162 mm inch tapered roller bearing — an ABMA-dimensioned cone/cup set, not an ISO 355 metric bearing, even though the table quotes metric equivalents. Cone and cup of 4T-36990/36920 are separately stocked parts: a worn 36920 cup can be replaced against the existing 36990 cone, provided the new cup carries the identical reference — pairing across references changes the 30.162 mm assembled width and the rating. Grease relubrication at the 1,300 r/min limiting speed targets the cone-rib contact; sustaining 1,800 r/min needs an oil supply directed at the large roller ends. Cup-side note for 36920: within the pure-numeric inch family tables the 36990 cone is listed against several cup options, and it is the cup that fixes the 227.012 mm OD and the 30.162 mm assembled width — quote the full 36990/36920 pair, never the cone alone. With a rotating shaft a m6/n6 cone seat and an easy-push cup seat are typical practice for 4T-36990/36920; reverse the fit logic when the cup rotates.
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
- 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
- rolling-contact fatigue spalling after the catalogue L10 life at the actual combined load
Selection pitfalls — read before you substitute
- At 177.8 mm bore the 4T-36990/36920 set is adjusted with hydraulic nuts or measured shims on mill and crane positions; manual torque methods cannot control preload at the 201 kN C level.
- The pure-numeric inch family at 177.8 mm bore (227.012×30.162 mm assembled) is one of several inch families sharing similar bores; cross-series swaps change OD, T and contact angle, so match the full 36990/36920 reference at purchase.
- Fit selection follows the rotating ring: a rotating cone on a 177.8 mm shaft takes a m6/n6 seat, and a rotating cup reverses the logic — decide from the load diagram, not from habit.
- Shaft and housing fillets must clear the ring chamfers of 36990 and 36920; use undercut shoulders so the rings seat on the face, not on a radius.
- An unloaded 4T-36990/36920 near 1,300 r/min lets rollers skid and smear the cone rib; spring-preload lightly loaded high-speed pairs.
- The 201/415 kN ratings here are NTN Ball and Roller Bearings CAT.No.2203E figures for 4T-36990/36920; 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-36990/36920?
4T-36990/36920 is an inch-series single-row tapered roller bearing to the ABMA boundary plan: 177.8 mm bore (7 in), 227.012 mm outside diameter and 30.162 mm assembled width T (8.937 × 1.187 in). From NTN Ball and Roller Bearings CAT.No.2203E: C 201 kN, C0 415 kN, grease limiting speed 1,300 r/min, oil speed 1,800 r/min, mass about 2910 g. It is an open, separable cone/cup set with a pressed-steel cage.
Are the cone and cup of 4T-36990/36920 interchangeable separately?
Yes — ABMA inch parts are individually interchangeable: the 36990 cone or the 36920 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 201/415 kN ratings change with the cup.
What is the difference between 4T-36990/36920 and a metric ISO 355 tapered bearing?
4T-36990/36920 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 177.8×227.012×30.162 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-36990/36920 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 36990/36920 references; the 4T spelling is retained among this page's search aliases.
Why does 4T-36990/36920 list two speeds, 1,300 and 1,800 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-36990/36920 at 1,800 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.