430311DX bearing: complete specifications & equivalents
The 430311DX is a ANSI ABMA 19.2 radial bearing sized 55 x 120 x 70 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | NTN |
| Bore diameter d | 55 mm |
| Outer diameter D | 120 mm |
| Width B | 70 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | steel |
| Basic dynamic load rating C | 251 kN |
| Basic static load rating C0 | 305 kN |
| Limiting speed (mechanical) | 2400 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 3420 g |
| Manufacturer designation | NTN 4T-430311DX |
| 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 | 2.165 in |
|---|---|
| Outer diameter D | 4.724 in |
| Width B | 2.756 in |
| ISO bore code | — |
| Radial section height (D−d)/2 | 32.5 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) | 4 of 41 |
| Bore above smallest 4t-430-series size | 15 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| 430311DX | 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 430311DX model number is decoded
4T-430311DX is the NTN 4T catalogue entry for a 55×120×70 mm double-row tapered roller bearing — the TDO arrangement reacts radial load plus thrust in both directions without a second bearing. Reading the designation: the last two digits 11 are the bore code, ×5 = 55 mm (codes 00–03 use the 10/12/15/17 exception table); the leading digits place the bearing in the light-duty 430-family TDO double-row series. The 32.5 mm radial section over the 55 mm bore carries two roller rows across the 70 mm width; abutment shoulders must clear both cone bores and the double-cup OD. Because the unit is preset, mounting 4T-430311DX resembles mounting a double-row spherical or cylindrical bearing: seat the unit, clamp axially to the stated end cover torque, and verify rotation — no end-play measurement is required. Fillet radii and shoulder heights must follow the 2203E mounting table for 4T-430311DX; the double cup must seat square across its full 70 mm width.
Typical equipment & failure modes
Common applications
- mining conveyor drive and head pulleys
- paper-machine roll and press supports
- extruder and mixer drive shafts
- construction-equipment swing and pivot shafts
Known failure patterns
- roller large-end smearing against the cone ribs when one row of the unit runs starved of lubricant
- one-row flaking when a bent shaft concentrates the combined load on a single row of the pair
- overheated running after a field attempt to "tighten up" the factory-set internal clearance
- cage damage when the unit is lifted by one cone instead of the double cup during fitting
- thermal distress when the oil supply sized for one row starves the second row
Selection pitfalls — read before you substitute
- Gearbox positions of this 55 mm class rely on the preset clearance of 4T-430311DX; 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-430311DX narrower and faster than the 432 heavy execution of the same 55 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 430311DX code including suffixes — U, X, DX, E1 and UTG variants share the 55 mm bore but are different articles with different internal geometry.
- Clamping the double cup with a cocked end cover pinches one row: tighten the 120 mm OD clamping uniformly around the circumference.
- An unloaded 4T-430311DX near 2,400 r/min lets rollers skid; ensure a minimum load or light spring preload on high-speed positions.
- The 251/305 kN ratings here are NTN Ball and Roller Bearings CAT.No.2203E figures for 4T-430311DX; 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-430311DX?
4T-430311DX is a double-row tapered roller bearing of TDO (back-to-back) construction: 55 mm bore, 120 mm outside diameter and 70 mm overall width. From NTN Ball and Roller Bearings CAT.No.2203E: C 251 kN, C0 305 kN (2203E prints a dash for Cu on this size), grease limiting speed 2,400 r/min, oil speed 3,100 r/min, mass about 3.42 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 55 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-430311DX 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-430311DX 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 70 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 430311DX mean?
Suffix reading on 430311DX: X marks the boundary-dimension revision of the base number (D and width differ from the plain number of the same bore); suffixed variants are separate order numbers and are not interchangeable articles.
Why does 4T-430311DX list two speeds, 2,400 and 3,100 r/min?
The lower figure, 2,400 r/min, is the grease-lubricated limiting speed for the two rows and their cages. With oil lubrication NTN rates 4T-430311DX at 3,100 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.