HM212046-HM212011 bearing: complete specifications & equivalents
The HM212046-HM212011 is a ANSI ABMA 19.2 radial bearing sized 63.5 x 122.238 x 38.1 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | NTN |
| Bore diameter d | 63.5 mm |
| Outer diameter D | 122.238 mm |
| Width B | 38.1 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | steel |
| Basic dynamic load rating C | 208 kN |
| Basic static load rating C0 | 244 kN |
| Limiting speed (mechanical) | 3100 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 1950 g |
| Manufacturer designation | NTN 4T-HM212046/HM212011 |
| 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 | 2.5 in |
|---|---|
| Outer diameter D | 4.813 in |
| Width B | 1.5 in |
| ISO bore code | 46 |
| Radial section height (D−d)/2 | 29.4 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) | 81 of 148 |
| Bore above smallest 4t-inch-series size | 50.8 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| HM212046 | 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 HM212046-HM212011 model number is decoded
For an inch shaft of 63.5 mm carrying combined radial and thrust load, NTN lists 4T-HM212046/HM212011, a single-row 4T tapered roller set of 208 kN C and 244 kN C0 inside the 122.238 mm OD cup. Unlike ISO 355 metric numbers, this ABMA code does not encode the bore arithmetically: HM212046 identifies the cone of 63.5 mm (2.5 in) bore by catalogue lookup, and HM212011 fixes the 122.238 mm OD. Speed planning uses both catalogue columns: grease 3,100 r/min is the mechanical ceiling for 4T-HM212046/HM212011, oil 4,100 r/min with circulating oil — a 1,000 r/min margin at this size. Cup-side note for HM212011: within the heavy-medium HM family tables the HM212046 cone is listed against several cup options, and it is the cup that fixes the 122.238 mm OD and the 38.1 mm assembled width — quote the full HM212046/HM212011 pair, never the cone alone. Fillet radii must clear the chamfers of the HM212046 cone and HM212011 cup; undercut shoulders seat the rings fully instead of bridging on a radius.
Typical equipment & failure modes
Common applications
- heavy truck and bus drive-axle differentials
- plant gearboxes on inch-dimensioned shaft lines
- large conveyor head pulleys in bulk-handling plant
- paper-machine and calender roll supports
Known failure patterns
- rib-face scoring when the thrust share of the combined load exceeds what the cone rib of this size carries
- false brinelling on a stationary pair exposed to vibration during transport or standby
- preload loss and noise after one bearing of the adjusted pair is replaced without resetting end play
- pressed-steel cage pocket wear from roller skid at light radial load and high speed
- brinell marks on cone and cup raceways from impact during handling or hammer fitting
Selection pitfalls — read before you substitute
- Mount the 63.5 mm cone by induction heating (max 120 °C) and the 122.238 mm cup with a press sleeve; at 1950 g a cocked ring brinells the raceway directly.
- The heavy-medium HM family is proportioned for a high thrust share; swapping to a lighter LM or pure-numeric series at the same 63.5 mm bore cuts axial capacity even when the envelope fits — re-verify the load split before downgrading.
- Inch and metric bores collide on paper — 63.5 mm is 2.5 in, not a round metric size; a metric bearing that seems 0.1 mm off will not seat on the inch shaft.
- ABMA makes the 63.5×122.238 mm envelope interchangeable, not the ratings: NTN prints 208/244 kN for this execution and another make of the same number can differ in roller complement.
- Never drive the 122.238 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 208/244 kN ratings here are NTN Ball and Roller Bearings CAT.No.2203E figures for 4T-HM212046/HM212011; 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-HM212046/HM212011?
4T-HM212046/HM212011 is an inch-series single-row tapered roller bearing to the ABMA boundary plan: 63.5 mm bore (2.5 in), 122.238 mm outside diameter and 38.1 mm assembled width T (4.813 × 1.5 in). From NTN Ball and Roller Bearings CAT.No.2203E: C 208 kN, C0 244 kN, grease limiting speed 3,100 r/min, oil speed 4,100 r/min, mass about 1950 g. It is an open, separable cone/cup set with a pressed-steel cage.
Are the cone and cup of 4T-HM212046/HM212011 interchangeable separately?
Yes — ABMA inch parts are individually interchangeable: the HM212046 cone or the HM212011 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 208/244 kN ratings change with the cup.
What is the difference between 4T-HM212046/HM212011 and a metric ISO 355 tapered bearing?
4T-HM212046/HM212011 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 63.5×122.238×38.1 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-HM212046/HM212011 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 HM212046/HM212011 references; the 4T spelling is retained among this page's search aliases.
Why does 4T-HM212046/HM212011 list two speeds, 3,100 and 4,100 r/min?
The lower figure, 3,100 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-HM212046/HM212011 at 4,100 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.