323068UTG bearing: complete specifications & equivalents
The 323068UTG is a ANSI ABMA 19.2 radial bearing sized 340 x 520 x 133 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | NTN |
| Bore diameter d | 340 mm |
| Outer diameter D | 520 mm |
| Width B | 133 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | steel |
| Basic dynamic load rating C | 2420 kN |
| Basic static load rating C0 | 3750 kN |
| Fatigue load limit Pu | 295 kN |
| Limiting speed (mechanical) | 490 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 100000 g |
| Manufacturer designation | NTN 4T-323068UTG |
| 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 | 13.386 in |
|---|---|
| Outer diameter D | 20.472 in |
| Width B | 5.236 in |
| ISO bore code | — |
| Radial section height (D−d)/2 | 90 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) | 31 of 39 |
| Bore above smallest 4t-432-series size | 300 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| 323068UTG | 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 323068UTG model number is decoded
In NTN Ball and Roller Bearings CAT.No.2203E, the order number 4T-323068UTG denotes the heavy-duty 432-family TDO double-row series — a 340 mm bore double-row tapered unit rated 2420 kN basic dynamic and 3750 kN static. Suffix reading on 323068UTG: 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. Selection: C 2420 kN against C0 3750 kN gives a C0/C ratio of 1.55; the two rows of 4T-323068UTG share the combined load as one bearing position. Because the unit is preset, mounting 4T-323068UTG 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. Induction heating to max 120 °C is the standard fitting method at this 340 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
- 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 fatigue after continuous running near the grease limiting speed without oil cooling
- rolling-contact fatigue spalling after the catalogue L10 life at the actual combined load
Selection pitfalls — read before you substitute
- At 340 mm bore the 4T-323068UTG unit needs hydraulic or crane-assisted fitting and a verified oil supply; manual methods cannot control seating at the 2420 kN C level.
- The 432 heavy plan gives 4T-323068UTG its 133 mm width and 2420 kN rating at the 340 mm bore; do not downgrade to a 430-family unit of the same bore without re-checking C, C0 and the 295 kN Cu.
- Lubricant must reach both rows: a housing groove aligned to the cup mid-width of 4T-323068UTG feeds the two roller complements evenly; a single-side feed starves the far row.
- Clamping the double cup with a cocked end cover pinches one row: tighten the 520 mm OD clamping uniformly around the circumference.
- Open 4T-323068UTG units have no seals: the housing must seal both rows or the 490 r/min grease figure is meaningless once contamination enters.
- The 2420/3750 kN ratings and 295 kN Cu here are NTN Ball and Roller Bearings CAT.No.2203E figures for 4T-323068UTG; 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-323068UTG?
4T-323068UTG is a double-row tapered roller bearing of TDO (back-to-back) construction: 340 mm bore, 520 mm outside diameter and 133 mm overall width. From NTN Ball and Roller Bearings CAT.No.2203E: C 2420 kN, C0 3750 kN, Cu 295 kN, grease limiting speed 490 r/min, oil speed 700 r/min, mass about 100 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 340 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-323068UTG 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-323068UTG 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 133 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 323068UTG mean?
Suffix reading on 323068UTG: 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-323068UTG list two speeds, 490 and 700 r/min?
The lower figure, 490 r/min, is the grease-lubricated limiting speed for the two rows and their cages. With oil lubrication NTN rates 4T-323068UTG at 700 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.