323024 bearing: complete specifications & equivalents
The 323024 is a ANSI ABMA 19.2 radial bearing sized 120 x 180 x 46 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | NTN |
| Bore diameter d | 120 mm |
| Outer diameter D | 180 mm |
| Width B | 46 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | steel |
| Basic dynamic load rating C | 255 kN |
| Basic static load rating C0 | 375 kN |
| Fatigue load limit Pu | 40 kN |
| Limiting speed (mechanical) | 1500 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 4080 g |
| Manufacturer designation | NTN 4T-323024 |
| 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-432-series range
| Bore d | 4.724 in |
|---|---|
| Outer diameter D | 7.087 in |
| Width B | 1.811 in |
| ISO bore code | 24 |
| Radial section height (D−d)/2 | 30 mm |
| Smallest bore in 4t-432-series | 40 mm |
| Largest outer diameter in 4t-432-series | 790 mm |
| Width range across 4t-432-series | 46–266 mm |
| Bore position in 4t-432-series (smallest first) | 16 of 39 |
| Bore above smallest 4t-432-series size | 80 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| 323024 | 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 323024 model number is decoded
4T-323024 is the NTN 4T catalogue entry for a 120×180×46 mm double-row tapered roller bearing — the TDO arrangement reacts radial load plus thrust in both directions without a second bearing. With no letter suffix, 323024 is the basic open double-row execution: steel cages, factory-set internal clearance, no feature suffix in the order code. Grease relubrication at the 1,500 r/min limiting speed must reach both roller rows; sustaining 2,100 r/min needs an oil supply with defined flow through the double cup. TDO construction means the two cone assemblies of 4T-323024 face away from each other inside one double cup: the load lines diverge outward, giving a wide effective spread and high moment stiffness for the 120 mm shaft. Axial clamping of the double cup must be uniform around the 180 mm OD; a cocked end cover pinches one row and destroys the factory clearance setting.
Typical equipment & failure modes
Common applications
- port-crane hoist and luffing gearboxes
- heavy press and forging-machine drives
- large shredder and recycler main shafts
- power-plant mill and fan shafts
Known failure patterns
- roller large-end smearing against the cone ribs when one row of the unit runs starved of lubricant
- brinelling of both rows from a mounting blow transmitted through the roller complements
- preload loss and hammering noise when the cup clamping loosens and the unit gains axial float
- cage damage when the unit is lifted by one cone instead of the double cup during fitting
- water-induced pitting when washdown reaches the open unit without external seals
Selection pitfalls — read before you substitute
- At 120 mm bore the 4T-323024 unit needs hydraulic or crane-assisted fitting and a verified oil supply; manual methods cannot control seating at the 255 kN C level.
- The 432 heavy plan gives 4T-323024 its 46 mm width and 255 kN rating at the 120 mm bore; do not downgrade to a 430-family unit of the same bore without re-checking C, C0 and the 40 kN Cu.
- An unloaded 4T-323024 near 1,500 r/min lets rollers skid; ensure a minimum load or light spring preload on high-speed positions.
- At inspection do not mix the cone assemblies of 4T-323024 with another unit; rows are ground together and re-matching is not guaranteed in the field.
- Lubricant must reach both rows: a housing groove aligned to the cup mid-width of 4T-323024 feeds the two roller complements evenly; a single-side feed starves the far row.
- The 255/375 kN ratings and 40 kN Cu here are NTN Ball and Roller Bearings CAT.No.2203E figures for 4T-323024; internal geometry legitimately differs between manufacturers, so re-verify ratings, clearance class and suffix before substituting another make on a rated drive.
Frequently asked questions
What are the dimensions and catalogue ratings of NTN 4T-323024?
4T-323024 is a double-row tapered roller bearing of TDO (back-to-back) construction: 120 mm bore, 180 mm outside diameter and 46 mm overall width. From NTN Ball and Roller Bearings CAT.No.2203E: C 255 kN, C0 375 kN, Cu 40 kN, grease limiting speed 1,500 r/min, oil speed 2,100 r/min, mass about 4.08 kg. It is an open, preset-clearance unit with pressed-steel cages.
What is the difference between the NTN 430 and 432 double-row series at 120 mm bore?
Both are TDO double-row tapered roller units, but 430 is the light plan and 432 the heavy plan: at the same bore the 432 execution is wider and heavier with higher load ratings. 4T-323024 belongs to the heavy-duty 432-family TDO double-row series. Large sizes continue the plans as 4130/4131/4230/4231 (430 family) and 3230/3231 (432 family).
Can the internal clearance of 4T-323024 be adjusted at mounting?
No. The TDO unit — two cone assemblies against one double cup — is ground and set by NTN at the factory, and the 46 mm overall width is the finished dimension. Mounting sets no end play: seat the unit square, clamp the cup uniformly and verify free rotation. Field re-adjustment overloads one row.
What do the suffix letters on 323024 mean?
With no letter suffix, 323024 is the basic open double-row execution: steel cages, factory-set internal clearance, no feature suffix in the order code.
Why does 4T-323024 list two speeds, 1,500 and 2,100 r/min?
The lower figure, 1,500 r/min, is the grease-lubricated limiting speed for the two rows and their cages. With oil lubrication NTN rates 4T-323024 at 2,100 r/min because oil removes heat from both roller rows better — the housing feed must reach both rows through the double cup.
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.