55187C-55437 bearing: complete specifications & equivalents
The 55187C-55437 is a ANSI ABMA 19.2 radial bearing sized 47.625 x 111.125 x 30.162 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | NTN |
| Bore diameter d | 47.625 mm |
| Outer diameter D | 111.125 mm |
| Width B | 30.162 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | steel |
| Basic dynamic load rating C | 115 kN |
| Basic static load rating C0 | 136 kN |
| Limiting speed (mechanical) | 3200 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 1400 g |
| Manufacturer designation | NTN 4T-55187C/55437 |
| 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 | 1.875 in |
|---|---|
| Outer diameter D | 4.375 in |
| Width B | 1.187 in |
| ISO bore code | — |
| Radial section height (D−d)/2 | 31.8 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) | 59 of 148 |
| Bore above smallest 4t-inch-series size | 34.925 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| 55187C | 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 55187C-55437 model number is decoded
4T-55187C/55437 belongs to the NTN inch 4T tapered roller range (pure-numeric inch family); cone and cup are ordered by their own references and are individually interchangeable with like-numbered parts. Unlike ISO 355 metric numbers, this ABMA code does not encode the bore arithmetically: 55187C identifies the cone of 47.625 mm (1.875 in) bore by catalogue lookup, and 55437 fixes the 111.125 mm OD. Two single-row inch sets are normally mounted as an adjusted O or X pair; the 30.162 mm T of each 4T-55187C/55437 enters the spacer calculation, so the tolerance on assembled width matters as much as the bore fit. The printed 115/136 kN ratings belong to the assembled 55187C+55437 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. Mount the 47.625 mm cone with an induction heater (max 120 °C) and press the 111.125 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
- cone-rib and roller large-end smearing when the adjusted pair runs with preload but starved lubricant film
- 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
- Hub and pinion positions of this 47.625 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-55187C/55437.
- The pure-numeric inch family at 47.625 mm bore (111.125×30.162 mm assembled) is one of several inch families sharing similar bores; cross-series swaps change OD, T and contact angle, so match the full 55187C/55437 reference at purchase.
- Replacing one half of an adjusted pair without resetting end play negates the 30.162 mm T logic: re-adjust the set and re-verify the contact pattern rather than reusing the old spacer stack.
- Shaft and housing fillets must clear the ring chamfers of 55187C and 55437; use undercut shoulders so the rings seat on the face, not on a radius.
- Never drive the 111.125 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 115/136 kN ratings here are NTN Ball and Roller Bearings CAT.No.2203E figures for 4T-55187C/55437; 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-55187C/55437?
4T-55187C/55437 is an inch-series single-row tapered roller bearing to the ABMA boundary plan: 47.625 mm bore (1.875 in), 111.125 mm outside diameter and 30.162 mm assembled width T (4.375 × 1.187 in). From NTN Ball and Roller Bearings CAT.No.2203E: C 115 kN, C0 136 kN, grease limiting speed 3,200 r/min, oil speed 4,200 r/min, mass about 1400 g. It is an open, separable cone/cup set with a pressed-steel cage.
Are the cone and cup of 4T-55187C/55437 interchangeable separately?
Yes — ABMA inch parts are individually interchangeable: the 55187C cone or the 55437 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 115/136 kN ratings change with the cup.
What is the difference between 4T-55187C/55437 and a metric ISO 355 tapered bearing?
4T-55187C/55437 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 47.625×111.125×30.162 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-55187C/55437 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 55187C/55437 references; the 4T spelling is retained among this page's search aliases.
Why does 4T-55187C/55437 list two speeds, 3,200 and 4,200 r/min?
The lower figure, 3,200 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-55187C/55437 at 4,200 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.