1755-1729 bearing: complete specifications & equivalents
The 1755-1729 is a ANSI ABMA 19.2 radial bearing sized 22.225 x 56.896 x 19.368 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | NTN |
| Bore diameter d | 22.225 mm |
| Outer diameter D | 56.896 mm |
| Width B | 19.368 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | steel |
| Basic dynamic load rating C | 47.5 kN |
| Basic static load rating C0 | 46.5 kN |
| Limiting speed (mechanical) | 7200 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 252 g |
| Manufacturer designation | NTN 4T-1755/1729 |
| 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 | 0.875 in |
|---|---|
| Outer diameter D | 2.24 in |
| Width B | 0.763 in |
| ISO bore code | — |
| Radial section height (D−d)/2 | 17.3 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) | 13 of 148 |
| Bore above smallest 4t-inch-series size | 9.525000000000002 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| 1755 | 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 1755-1729 model number is decoded
The NTN 2203E inch table prints 4T-1755/1729 at 22.225 mm bore (0.875 in), 56.896 mm cup OD and 19.368 mm assembled T, with a grease limiting speed of 7,200 r/min and an oil ceiling of 9,600 r/min. Unlike ISO 355 metric numbers, this ABMA code does not encode the bore arithmetically: 1755 identifies the cone of 22.225 mm (0.875 in) bore by catalogue lookup, and 1729 fixes the 56.896 mm OD. Contact-angle geometry of the pure-numeric inch family gives 4T-1755/1729 its radial/axial load split — at 47.5/46.5 kN the static rating is about 0.98× C, typical of inch tapered sets proportioned for combined duty. Cup-side note for 1729: within the pure-numeric inch family tables the 1755 cone is listed against several cup options, and it is the cup that fixes the 56.896 mm OD and the 19.368 mm assembled width — quote the full 1755/1729 pair, never the cone alone. With a rotating shaft a k5/m5 cone seat and an easy-push cup seat are typical practice for 4T-1755/1729; reverse the fit logic when the cup rotates.
Typical equipment & failure modes
Common applications
- light trailer and boat-trailer wheel hubs
- small agricultural implement wheels and auger drives
- lawn, garden and powersport axle positions
- small inch-shaft gearbox and reducer shafts
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
- cage damage from a mounting blow transmitted through the roller complement
- brinell marks on cone and cup raceways from impact during handling or hammer fitting
Selection pitfalls — read before you substitute
- At 22.225 mm (0.875 in) bore the thin cone and cup distort under an over-tight shaft nut; set the 4T-1755/1729 pair with a dial indicator on end play rather than by locknut feel.
- The pure-numeric inch family at 22.225 mm bore (56.896×19.368 mm assembled) is one of several inch families sharing similar bores; cross-series swaps change OD, T and contact angle, so match the full 1755/1729 reference at purchase.
- Never drive the 56.896 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.
- Never drive the 56.896 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.
- Grease packs must leave free volume inside the 19.368 mm-wide set; over-greasing a pair churning near the oil-band speed of 9,600 r/min raises temperature and destroys the setting.
- The 47.5/46.5 kN ratings here are NTN Ball and Roller Bearings CAT.No.2203E figures for 4T-1755/1729; 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-1755/1729?
4T-1755/1729 is an inch-series single-row tapered roller bearing to the ABMA boundary plan: 22.225 mm bore (0.875 in), 56.896 mm outside diameter and 19.368 mm assembled width T (2.24 × 0.763 in). From NTN Ball and Roller Bearings CAT.No.2203E: C 47.5 kN, C0 46.5 kN, grease limiting speed 7,200 r/min, oil speed 9,600 r/min, mass about 252 g. It is an open, separable cone/cup set with a pressed-steel cage.
Are the cone and cup of 4T-1755/1729 interchangeable separately?
Yes — ABMA inch parts are individually interchangeable: the 1755 cone or the 1729 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 47.5/46.5 kN ratings change with the cup.
What is the difference between 4T-1755/1729 and a metric ISO 355 tapered bearing?
4T-1755/1729 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 22.225×56.896×19.368 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-1755/1729 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 1755/1729 references; the 4T spelling is retained among this page's search aliases.
Why does 4T-1755/1729 list two speeds, 7,200 and 9,600 r/min?
The lower figure, 7,200 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-1755/1729 at 9,600 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.