HM813840-HM813810 bearing: complete specifications & equivalents
The HM813840-HM813810 is a ANSI ABMA 19.2 radial bearing sized 55.562 x 127 x 36.512 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | NTN |
| Bore diameter d | 55.562 mm |
| Outer diameter D | 127 mm |
| Width B | 36.512 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | steel |
| Basic dynamic load rating C | 181 kN |
| Basic static load rating C0 | 228 kN |
| Limiting speed (mechanical) | 2900 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 2340 g |
| Manufacturer designation | NTN 4T-HM813840/HM813810 |
| 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 | 2.187 in |
|---|---|
| Outer diameter D | 5 in |
| Width B | 1.437 in |
| ISO bore code | 40 |
| Radial section height (D−d)/2 | 35.7 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) | 70 of 148 |
| Bore above smallest 4t-inch-series size | 42.861999999999995 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| HM813840 | 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 HM813840-HM813810 model number is decoded
The NTN 2203E inch table prints 4T-HM813840/HM813810 at 55.562 mm bore (2.187 in), 127 mm cup OD and 36.512 mm assembled T, with a grease limiting speed of 2,900 r/min and an oil ceiling of 3,800 r/min. Unlike ISO 355 metric numbers, this ABMA code does not encode the bore arithmetically: HM813840 identifies the cone of 55.562 mm (2.187 in) bore by catalogue lookup, and HM813810 fixes the 127 mm OD. Imperial cross-check for the drawing: 55.562×127×36.512 mm converts to 2.187 × 5 × 1.437 in; the ABMA envelope swaps with like-numbered inch parts but the 181/228 kN ratings are NTN-specific. The printed 181/228 kN ratings belong to the assembled HM813840+HM813810 pair; a sibling row using the same cone with a different cup carries its own rating row because the raceway track shifts with the cup. The rollers run with their large ends against the cone's guide rib; lubricant must reach that rib face of 4T-HM813840/HM813810, not only the raceway, or the pair smears on the first overloaded start.
Typical equipment & failure modes
Common applications
- paper-machine and calender roll supports
- off-highway and forestry machine axles
- marine winch and deck-machinery shafts
- crusher and screening-plant eccentric shafts
Known failure patterns
- rib-face scoring when the thrust share of the combined load exceeds what the cone rib of this size carries
- 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
- water-induced pitting when the open bearing sees washdown without external seals
Selection pitfalls — read before you substitute
- Mount the 55.562 mm cone by induction heating (max 120 °C) and the 127 mm cup with a press sleeve; at 2340 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 55.562 mm bore cuts axial capacity even when the envelope fits — re-verify the load split before downgrading.
- ABMA makes the 55.562×127 mm envelope interchangeable, not the ratings: NTN prints 181/228 kN for this execution and another make of the same number can differ in roller complement.
- Fit selection follows the rotating ring: a rotating cone on a 55.562 mm shaft takes a k5/m5 seat, and a rotating cup reverses the logic — decide from the load diagram, not from habit.
- Open 4T-HM813840/HM813810 sets have no seals: a hub or gearbox needs external sealing or the 2,900 r/min grease figure is meaningless once water reaches the cone rib.
- The 181/228 kN ratings here are NTN Ball and Roller Bearings CAT.No.2203E figures for 4T-HM813840/HM813810; 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-HM813840/HM813810?
4T-HM813840/HM813810 is an inch-series single-row tapered roller bearing to the ABMA boundary plan: 55.562 mm bore (2.187 in), 127 mm outside diameter and 36.512 mm assembled width T (5 × 1.437 in). From NTN Ball and Roller Bearings CAT.No.2203E: C 181 kN, C0 228 kN, grease limiting speed 2,900 r/min, oil speed 3,800 r/min, mass about 2340 g. It is an open, separable cone/cup set with a pressed-steel cage.
Are the cone and cup of 4T-HM813840/HM813810 interchangeable separately?
Yes — ABMA inch parts are individually interchangeable: the HM813840 cone or the HM813810 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 181/228 kN ratings change with the cup.
What is the difference between 4T-HM813840/HM813810 and a metric ISO 355 tapered bearing?
4T-HM813840/HM813810 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 55.562×127×36.512 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-HM813840/HM813810 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 HM813840/HM813810 references; the 4T spelling is retained among this page's search aliases.
Why does 4T-HM813840/HM813810 list two speeds, 2,900 and 3,800 r/min?
The lower figure, 2,900 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-HM813840/HM813810 at 3,800 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.