366-362A bearing: complete specifications & equivalents
The 366-362A is a ANSI ABMA 19.2 radial bearing sized 50 x 88.9 x 20.638 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | NTN |
| Bore diameter d | 50 mm |
| Outer diameter D | 88.9 mm |
| Width B | 20.638 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | steel |
| Basic dynamic load rating C | 85 kN |
| Basic static load rating C0 | 90.5 kN |
| Limiting speed (mechanical) | 4100 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 530 g |
| Manufacturer designation | NTN 4T-366/362A |
| 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 | 1.969 in |
|---|---|
| Outer diameter D | 3.5 in |
| Width B | 0.813 in |
| ISO bore code | 66 |
| Radial section height (D−d)/2 | 19.5 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) | 63 of 148 |
| Bore above smallest 4t-inch-series size | 37.3 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| 366 | 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 366-362A model number is decoded
NTN supplies this 1.969 in (50 mm) shaft position as 4T-366/362A: cone 366, cup 362A, profiled rollers and a pressed-steel cage, rated 85 kN basic dynamic and 90.5 kN static. The 4T prefix is NTN's tapered roller quality mark stamped on both parts; it is a brand mark, not a size code, so cross-references quote 366/362A without it. Catalogue mass of the 4T-366/362A cone-plus-cup set is 530 g; shaft and housing shoulders must carry that mass square to the axis during fitting. Housing fitment sequence for 4T-366/362A: press the 362A cup square into the 88.9 mm seat first, then bring the 366 cone (on its 50 mm shaft) into adjustment — the two references are separate engineering parts that happen to ship as one set. Minimum load matters at speed: an unloaded 4T-366/362A run near 4,100 r/min lets the rollers skid; lightly spring-preload high-speed pair arrangements.
Typical equipment & failure modes
Common applications
- industrial gearboxes built to inch shafting
- construction-equipment pivot and wheel positions
- mining and quarry conveyor drive pulleys
- machine-tool headstocks on inch spindles
Known failure patterns
- cone-rib and roller large-end smearing when the adjusted pair runs with preload but starved lubricant film
- preload loss and noise after one bearing of the adjusted pair is replaced without resetting end play
- false brinelling on a stationary pair exposed to vibration during transport or standby
- 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
- Hub and pinion positions of this 50 mm class are adjusted in pairs; verify end play against the axle or gearbox drawing and re-torque after bedding-in instead of trusting the first setting on 4T-366/362A.
- The pure-numeric inch family at 50 mm bore (88.9×20.638 mm assembled) is one of several inch families sharing similar bores; cross-series swaps change OD, T and contact angle, so match the full 366/362A reference at purchase.
- Fit selection follows the rotating ring: a rotating cone on a 50 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 50 mm shaft takes a k5/m5 seat, and a rotating cup reverses the logic — decide from the load diagram, not from habit.
- Never drive the 88.9 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.
- The 85/90.5 kN ratings here are NTN Ball and Roller Bearings CAT.No.2203E figures for 4T-366/362A; 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-366/362A?
4T-366/362A is an inch-series single-row tapered roller bearing to the ABMA boundary plan: 50 mm bore (1.969 in), 88.9 mm outside diameter and 20.638 mm assembled width T (3.5 × 0.813 in). From NTN Ball and Roller Bearings CAT.No.2203E: C 85 kN, C0 90.5 kN, grease limiting speed 4,100 r/min, oil speed 5,500 r/min, mass about 530 g. It is an open, separable cone/cup set with a pressed-steel cage.
Are the cone and cup of 4T-366/362A interchangeable separately?
Yes — ABMA inch parts are individually interchangeable: the 366 cone or the 362A 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 85/90.5 kN ratings change with the cup.
What is the difference between 4T-366/362A and a metric ISO 355 tapered bearing?
4T-366/362A 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 50×88.9×20.638 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-366/362A 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 366/362A references; the 4T spelling is retained among this page's search aliases.
Why does 4T-366/362A list two speeds, 4,100 and 5,500 r/min?
The lower figure, 4,100 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-366/362A at 5,500 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.