27690-27620 bearing: complete specifications & equivalents
The 27690-27620 is a ANSI ABMA 19.2 radial bearing sized 83.345 x 125.412 x 25.4 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | NTN |
| Bore diameter d | 83.345 mm |
| Outer diameter D | 125.412 mm |
| Width B | 25.4 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | steel |
| Basic dynamic load rating C | 113 kN |
| Basic static load rating C0 | 163 kN |
| Limiting speed (mechanical) | 2700 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 1030 g |
| Manufacturer designation | NTN 4T-27690/27620 |
| 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 | 3.281 in |
|---|---|
| Outer diameter D | 4.937 in |
| Width B | 1 in |
| ISO bore code | — |
| Radial section height (D−d)/2 | 21 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) | 100 of 148 |
| Bore above smallest 4t-inch-series size | 70.645 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| 27690 | 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 27690-27620 model number is decoded
4T-27690/27620 is the NTN 4T catalogue entry for a 83.345×125.412×25.4 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: 27690 identifies the cone of 83.345 mm (3.281 in) bore by catalogue lookup, and 27620 fixes the 125.412 mm OD. Catalogue mass of the 4T-27690/27620 cone-plus-cup set is 1030 g; shaft and housing shoulders must carry that mass square to the axis during fitting. Cup-side note for 27620: within the pure-numeric inch family tables the 27690 cone is listed against several cup options, and it is the cup that fixes the 125.412 mm OD and the 25.4 mm assembled width — quote the full 27690/27620 pair, never the cone alone. Mount the 83.345 mm cone with an induction heater (max 120 °C) and press the 125.412 mm cup with a sleeve; driving either ring through the rollers brinells the raceways.
Typical equipment & failure modes
Common applications
- marine winch and deck-machinery shafts
- crusher and screening-plant eccentric shafts
- heavy truck and bus drive-axle differentials
- plant gearboxes on inch-dimensioned shaft lines
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 fatigue when the pair runs continuously near the grease limiting speed without oil cooling
- rolling-contact fatigue spalling after the catalogue L10 life at the actual combined load
Selection pitfalls — read before you substitute
- Mount the 83.345 mm cone by induction heating (max 120 °C) and the 125.412 mm cup with a press sleeve; at 1030 g a cocked ring brinells the raceway directly.
- The pure-numeric inch family at 83.345 mm bore (125.412×25.4 mm assembled) is one of several inch families sharing similar bores; cross-series swaps change OD, T and contact angle, so match the full 27690/27620 reference at purchase.
- Fit selection follows the rotating ring: a rotating cone on a 83.345 mm shaft takes a k5/m5 seat, and a rotating cup reverses the logic — decide from the load diagram, not from habit.
- Fit selection follows the rotating ring: a rotating cone on a 83.345 mm shaft takes a k5/m5 seat, and a rotating cup reverses the logic — decide from the load diagram, not from habit.
- ABMA makes the 83.345×125.412 mm envelope interchangeable, not the ratings: NTN prints 113/163 kN for this execution and another make of the same number can differ in roller complement.
- The 113/163 kN ratings here are NTN Ball and Roller Bearings CAT.No.2203E figures for 4T-27690/27620; 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-27690/27620?
4T-27690/27620 is an inch-series single-row tapered roller bearing to the ABMA boundary plan: 83.345 mm bore (3.281 in), 125.412 mm outside diameter and 25.4 mm assembled width T (4.937 × 1 in). From NTN Ball and Roller Bearings CAT.No.2203E: C 113 kN, C0 163 kN, grease limiting speed 2,700 r/min, oil speed 3,600 r/min, mass about 1030 g. It is an open, separable cone/cup set with a pressed-steel cage.
Are the cone and cup of 4T-27690/27620 interchangeable separately?
Yes — ABMA inch parts are individually interchangeable: the 27690 cone or the 27620 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 113/163 kN ratings change with the cup.
What is the difference between 4T-27690/27620 and a metric ISO 355 tapered bearing?
4T-27690/27620 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 83.345×125.412×25.4 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-27690/27620 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 27690/27620 references; the 4T spelling is retained among this page's search aliases.
Why does 4T-27690/27620 list two speeds, 2,700 and 3,600 r/min?
The lower figure, 2,700 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-27690/27620 at 3,600 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.