430308 bearing: complete specifications & equivalents
The 430308 is a ANSI ABMA 19.2 radial bearing sized 40 x 90 x 56 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | NTN |
| Bore diameter d | 40 mm |
| Outer diameter D | 90 mm |
| Width B | 56 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | steel |
| Basic dynamic load rating C | 174 kN |
| Basic static load rating C0 | 204 kN |
| Limiting speed (mechanical) | 3700 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 1700 g |
| Manufacturer designation | NTN 4T-430308 |
| 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-430-series range
| Bore d | 1.575 in |
|---|---|
| Outer diameter D | 3.543 in |
| Width B | 2.205 in |
| ISO bore code | 08 |
| Radial section height (D−d)/2 | 25 mm |
| Smallest bore in 4t-430-series | 40 mm |
| Largest outer diameter in 4t-430-series | 870 mm |
| Width range across 4t-430-series | 45–310 mm |
| Bore position in 4t-430-series (smallest first) | 1 of 41 |
| Bore above smallest 4t-430-series size | 0 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| 430308 | 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 430308 model number is decoded
For a 40 mm shaft needing a compact two-direction thrust location, NTN lists 4T-430308, a TDO double-row 4T unit of 174 kN C and 204 kN C0 in the light-duty 430-family TDO double-row series. Unlike a pair of single-row bearings, the TDO unit of 4T-430308 integrates both rows in one article: the 56 mm overall width and the internal clearance are ground and set by NTN, so there is no field adjustment dimension. Grease relubrication at the 3,700 r/min limiting speed must reach both roller rows; sustaining 4,900 r/min needs an oil supply with defined flow through the double cup. The internal clearance of 4T-430308 is set at the factory by the double cup and spacer-less grinding; do not attempt to re-adjust it with shaft nuts — the 56 mm overall width is the finished dimension. The preset clearance suits the standard temperature range; unusual thermal gradients between shaft and housing call for a clearance review against the 40 mm size before ordering 4T-430308.
Typical equipment & failure modes
Common applications
- paper-machine roll and press supports
- extruder and mixer drive shafts
- construction-equipment swing and pivot shafts
- industrial gearbox shafts in a single locating position
Known failure patterns
- edge loading on one row when the housing seats the double cup cocked across its width
- preload loss and hammering noise when the cup clamping loosens and the unit gains axial float
- brinelling of both rows from a mounting blow transmitted through the roller complements
- cage damage when the unit is lifted by one cone instead of the double cup during fitting
- indentation of both raceways by hard particles in an open, unsealed arrangement
Selection pitfalls — read before you substitute
- Gearbox positions of this 40 mm class rely on the preset clearance of 4T-430308; shimming or nut-tightening the unit like a single-row pair overruns the factory setting and runs the rows hot.
- The 430 light plan keeps 4T-430308 narrower and faster than the 432 heavy execution of the same 40 mm bore; where shock or a high thrust share dominates, verify whether the heavier 432-family row is the intended position.
- Order by the full 430308 code including suffixes — U, X, DX, E1 and UTG variants share the 40 mm bore but are different articles with different internal geometry.
- Lubricant must reach both rows: a housing groove aligned to the cup mid-width of 4T-430308 feeds the two roller complements evenly; a single-side feed starves the far row.
- The 174 kN C already includes two-row load sharing — do not double it when pairing the unit with a floating bearing in the L10 calculation.
- The 174/204 kN ratings here are NTN Ball and Roller Bearings CAT.No.2203E figures for 4T-430308; 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-430308?
4T-430308 is a double-row tapered roller bearing of TDO (back-to-back) construction: 40 mm bore, 90 mm outside diameter and 56 mm overall width. From NTN Ball and Roller Bearings CAT.No.2203E: C 174 kN, C0 204 kN (2203E prints a dash for Cu on this size), grease limiting speed 3,700 r/min, oil speed 4,900 r/min, mass about 1.7 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 40 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-430308 belongs to the light-duty 430-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-430308 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 56 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 430308 mean?
With no letter suffix, 430308 is the basic open double-row execution: steel cages, factory-set internal clearance, no feature suffix in the order code.
Why does 4T-430308 list two speeds, 3,700 and 4,900 r/min?
The lower figure, 3,700 r/min, is the grease-lubricated limiting speed for the two rows and their cages. With oil lubrication NTN rates 4T-430308 at 4,900 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.