33889-33821 bearing: complete specifications & equivalents
The 33889-33821 is a ANSI ABMA 19.2 radial bearing sized 50.8 x 95.25 x 27.783 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | NTN |
| Bore diameter d | 50.8 mm |
| Outer diameter D | 95.25 mm |
| Width B | 27.783 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | steel |
| Basic dynamic load rating C | 119 kN |
| Basic static load rating C0 | 139 kN |
| Limiting speed (mechanical) | 3900 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 878 g |
| Manufacturer designation | NTN 4T-33889/33821 |
| 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 | 2 in |
|---|---|
| Outer diameter D | 3.75 in |
| Width B | 1.094 in |
| ISO bore code | — |
| Radial section height (D−d)/2 | 22.2 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) | 64 of 148 |
| Bore above smallest 4t-inch-series size | 38.099999999999994 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| 33889 | 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 33889-33821 model number is decoded
4T-33889/33821 is an NTN inch-series single-row tapered roller bearing: a separable cone-and-cup pair on the ABMA inch boundary plan, 50.8×95.25×27.783 mm (assembled width T), for a shaft of about 50.8 mm (2 in). Unlike ISO 355 metric numbers, this ABMA code does not encode the bore arithmetically: 33889 identifies the cone of 50.8 mm (2 in) bore by catalogue lookup, and 33821 fixes the 95.25 mm OD. The 22.2 mm radial section over the 50.8 mm bore positions the contact line of the pair; abutment shoulders and spacers are dimensioned from that geometry, not from the bore alone. Housing fitment sequence for 4T-33889/33821: press the 33821 cup square into the 95.25 mm seat first, then bring the 33889 cone (on its 50.8 mm shaft) into adjustment — the two references are separate engineering parts that happen to ship as one set. Mount the 50.8 mm cone with an induction heater (max 120 °C) and press the 95.25 mm cup with a sleeve; driving either ring through the rollers brinells the raceways.
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
- rib-face scoring when the thrust share of the combined load exceeds what the cone rib of this size carries
- 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
- pressed-steel cage pocket wear from roller skid at light radial load and high speed
- fretting corrosion on a loose cone seat that creeps under rotating load
Selection pitfalls — read before you substitute
- Hub and pinion positions of this 50.8 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-33889/33821.
- The pure-numeric inch family at 50.8 mm bore (95.25×27.783 mm assembled) is one of several inch families sharing similar bores; cross-series swaps change OD, T and contact angle, so match the full 33889/33821 reference at purchase.
- Never drive the 95.25 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.
- Open 4T-33889/33821 sets have no seals: a hub or gearbox needs external sealing or the 3,900 r/min grease figure is meaningless once water reaches the cone rib.
- Replacing one half of an adjusted pair without resetting end play negates the 27.783 mm T logic: re-adjust the set and re-verify the contact pattern rather than reusing the old spacer stack.
- The 119/139 kN ratings here are NTN Ball and Roller Bearings CAT.No.2203E figures for 4T-33889/33821; 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-33889/33821?
4T-33889/33821 is an inch-series single-row tapered roller bearing to the ABMA boundary plan: 50.8 mm bore (2 in), 95.25 mm outside diameter and 27.783 mm assembled width T (3.75 × 1.094 in). From NTN Ball and Roller Bearings CAT.No.2203E: C 119 kN, C0 139 kN, grease limiting speed 3,900 r/min, oil speed 5,200 r/min, mass about 878 g. It is an open, separable cone/cup set with a pressed-steel cage.
Are the cone and cup of 4T-33889/33821 interchangeable separately?
Yes — ABMA inch parts are individually interchangeable: the 33889 cone or the 33821 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 119/139 kN ratings change with the cup.
What is the difference between 4T-33889/33821 and a metric ISO 355 tapered bearing?
4T-33889/33821 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 50.8×95.25×27.783 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-33889/33821 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 33889/33821 references; the 4T spelling is retained among this page's search aliases.
Why does 4T-33889/33821 list two speeds, 3,900 and 5,200 r/min?
The lower figure, 3,900 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-33889/33821 at 5,200 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.