323188UTG bearing: complete specifications & equivalents
The 323188UTG is a ANSI ABMA 19.2 radial bearing sized 440 x 720 x 226 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | NTN |
| Bore diameter d | 440 mm |
| Outer diameter D | 720 mm |
| Width B | 226 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | steel |
| Basic dynamic load rating C | 6400 kN |
| Basic static load rating C0 | 10300 kN |
| Fatigue load limit Pu | 740 kN |
| Limiting speed (mechanical) | 340 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 360000 g |
| Manufacturer designation | NTN 4T-323188UTG |
| 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 | 17.323 in |
|---|---|
| Outer diameter D | 28.346 in |
| Width B | 8.898 in |
| ISO bore code | — |
| Radial section height (D−d)/2 | 140 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) | 36 of 39 |
| Bore above smallest 4t-432-series size | 400 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| 323188UTG | 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 323188UTG model number is decoded
In NTN Ball and Roller Bearings CAT.No.2203E, the order number 4T-323188UTG denotes the heavy-duty 432-family TDO double-row series — a 440 mm bore double-row tapered unit rated 6400 kN basic dynamic and 10300 kN static. Suffix reading on 323188UTG: UTG marks the ULTAGE specification for large NTN tapered rollers — upgraded material and internal design, printed with the ＊ symbol ahead of the order number; suffixed variants are separate order numbers and are not interchangeable articles. Grease relubrication at the 340 r/min limiting speed must reach both roller rows; sustaining 480 r/min needs an oil supply with defined flow through the double cup. TDO construction means the two cone assemblies of 4T-323188UTG 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 440 mm shaft. Induction heating to max 120 °C is the standard fitting method at this 440 mm bore; driving the unit home through the rollers brinells both rows at once.
Typical equipment & failure modes
Common applications
- large shredder and recycler main shafts
- power-plant mill and fan shafts
- rolling-mill roll-neck and pinion-stand positions
- mine hoist and dragline drum shafts
Known failure patterns
- edge loading on one row when the housing seats the double cup cocked across its width
- 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
- pressed-steel cage pocket wear from roller skid at light load and high speed
- water-induced pitting when washdown reaches the open unit without external seals
Selection pitfalls — read before you substitute
- At 440 mm bore the 4T-323188UTG unit needs hydraulic or crane-assisted fitting and a verified oil supply; manual methods cannot control seating at the 6400 kN C level.
- The 432 heavy plan gives 4T-323188UTG its 226 mm width and 6400 kN rating at the 440 mm bore; do not downgrade to a 430-family unit of the same bore without re-checking C, C0 and the 740 kN Cu.
- An unloaded 4T-323188UTG near 340 r/min lets rollers skid; ensure a minimum load or light spring preload on high-speed positions.
- The 6400 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 internal clearance of 4T-323188UTG is factory-set: no end-play adjustment exists at mounting, and any attempt to set preload with a shaft nut overloads one row.
- The 6400/10300 kN ratings and 740 kN Cu here are NTN Ball and Roller Bearings CAT.No.2203E figures for 4T-323188UTG; 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-323188UTG?
4T-323188UTG is a double-row tapered roller bearing of TDO (back-to-back) construction: 440 mm bore, 720 mm outside diameter and 226 mm overall width. From NTN Ball and Roller Bearings CAT.No.2203E: C 6400 kN, C0 10300 kN, Cu 740 kN, grease limiting speed 340 r/min, oil speed 480 r/min, mass about 360 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 440 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-323188UTG 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-323188UTG 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 226 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 323188UTG mean?
Suffix reading on 323188UTG: UTG marks the ULTAGE specification for large NTN tapered rollers — upgraded material and internal design, printed with the ＊ symbol ahead of the order number; suffixed variants are separate order numbers and are not interchangeable articles.
Why does 4T-323188UTG list two speeds, 340 and 480 r/min?
The lower figure, 340 r/min, is the grease-lubricated limiting speed for the two rows and their cages. With oil lubrication NTN rates 4T-323188UTG at 480 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.