30234UUTG bearing: complete specifications & equivalents
The 30234UUTG is a ISO 355 radial bearing sized 170 x 310 x 57 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | NTN |
| Bore diameter d | 170 mm |
| Outer diameter D | 310 mm |
| Width B | 57 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | steel |
| Basic dynamic load rating C | 780 kN |
| Basic static load rating C0 | 845 kN |
| Fatigue load limit Pu | 79.5 kN |
| Limiting speed (mechanical) | 1100 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 16900 g |
| Manufacturer designation | NTN 30234UUTG |
| Standard | ISO 355 |
| Catalog version | NTN Ball and Roller Bearings CAT.No.2203E |
| Last verified | 2026-10-01 |
Source: catalog reference (NTN Ball and Roller Bearings CAT.No.2203E) · extracted 2026-10-01
Parameters extracted from the official NTN Ball and Roller Bearings catalogue (NTN Ball and Roller Bearings CAT.No.2203E); 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 & 30200-series range
| Bore d | 6.693 in |
|---|---|
| Outer diameter D | 12.205 in |
| Width B | 2.244 in |
| ISO bore code | — |
| Radial section height (D−d)/2 | 70 mm |
| Smallest bore in 30200-series | 15 mm |
| Largest outer diameter in 30200-series | 580 mm |
| Width range across 30200-series | 11.75–104 mm |
| Bore position in 30200-series (smallest first) | 28 of 37 |
| Bore above smallest 30200-series size | 155 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| 30234UUTG | ISO 15 | full Dimensions and internal design equivalent — standard interchange. | ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier. |
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 30234UUTG model number is decoded
30234UUTG belongs to the NTN metric 4T tapered roller range (standard-section 30200 family); the open bearing leaves sealing to the application and is normally ordered and mounted as an adjustable matched pair. Reading the designation: the leading five digits follow the ISO 355 metric plan (dimension family plus two-digit bore code), and 30234UUTG resolves to 170 mm bore; the NTN factory mark 4T is stamped on cone and cup but is a brand mark, not a size code, so the catalogue sku is printed without it. A tapered roller bearing reacts combined radial and one-direction axial load; NTN mounts 30234UUTG cone and cup separately and adjusts end play or preload against a second bearing, so the arrangement locates the shaft in both directions. The fatigue load limit Pu printed for 30234UUTG is 79.5 kN; in the adjusted-life equation that is the equivalent-load floor below which high reliability is expected even under contamination. After mounting check the contact pattern with marking blue: a pattern biased to the large or small roller end means the 170 mm pair is misadjusted and the 57 mm T set will edge-load in service.
Typical equipment & failure modes
Common applications
- offshore crane and drawworks drums
- heavy haul railway traction gearboxes
- large marine propulsion reduction gears
- cement-plant kiln and mill drive trains
Known failure patterns
- cup creep and housing fretting when the specified outer-ring press fit is not achieved
- flaking on one cone only when a back-to-back / face-to-face pair is loaded unevenly by a bent shaft
- smearing on the roller large ends and cone rib after a dry start with preload but no oil film
- cage fatigue when the pair is run continuously near the grease limiting speed without oil cooling
- rolling-contact fatigue after the catalogue L10 life at the actual combined load
Selection pitfalls — read before you substitute
- At 170 mm bore the 30234UUTG set is adjusted with hydraulic nuts on large mill and wind positions; follow the drive-up angle/end-play procedure, because manual torque methods cannot control preload at the 780 kN C level.
- The standard-section 30200 family at 170 mm bore (310×57 mm assembled) carries more capacity than the lighter 320/329 sections but generates more preload heat; confirm oil availability before running near the 1,600 r/min oil ceiling.
- Grease packs must leave free volume in the 57 mm-wide set; over-greasing a paired bearing churning at the 1,600 r/min oil-band speed raises temperature and destroys the preload setting.
- Replacing one half of an adjusted pair without resetting end play negates the 57 mm T dimension logic: re-adjust the set and re-verify the contact pattern rather than reusing the old spacer stack.
- Do not confuse T (57 mm assembled width of cone + cup) with the cone width when drawing spacers; an abutment sized to T instead of the ring width leaves the cup unseated.
- The 780/845 kN ratings and 79.5 kN Pu here are NTN Ball and Roller Bearings CAT.No.2203E figures for 30234UUTG (ISO 355 4GB); internal geometry legitimately differs between manufacturers, so re-verify ratings, adjustment and suffix before substituting another make on a rated drive.
Frequently asked questions
What are the dimensions and catalogue ratings of NTN 30234UUTG?
30234UUTG is a metric 4T tapered roller bearing to ISO 355: 170 mm bore, 310 mm outside diameter and 57 mm assembled width T (6.693 × 12.205 × 2.244 in). From NTN Ball and Roller Bearings CAT.No.2203E: C 780 kN, C0 845 kN, Pu 79.5 kN, grease limiting speed 1,100 r/min, oil speed 1,600 r/min, mass about 16900 g. It is an open, separable cone/cup bearing with a pressed-steel cage.
What does the 4T prefix mean on 30234UUTG?
4T is NTN's tapered roller bearing brand mark, stamped on the cone and cup in the factory. It identifies the NTN 4T programme and is not a dimension, so the catalogue and this page list the bare ISO 355 number (30234UUTG); the lower-case 4t- factory spelling of the code is retained among the search aliases.
How does the 30234UUTG designation encode the 170 mm bore and what is 4GB?
last two digits 34 are the ISO bore code, ×5 = 170 mm (codes 00–03 use the 10/12/15/17 exception table). The 310 mm OD and 57 mm assembled T follow the ISO 355 dimension-series plan. 4GB is the maker-neutral ISO 355 abbreviation for this dimension series (the same code other manufacturers print); 4T is NTN's own brand mark.
Why does 30234UUTG list two speeds, 1,100 and 1,600 r/min?
The lower figure, 1,100 r/min, is the grease-lubricated limiting speed — the mechanical ceiling for the cage, rollers and cone-rib contact. With oil lubrication NTN rates 30234UUTG at 1,600 r/min because oil removes rib-contact heat better. Real limits still depend on preload, oil flow and cooling.
What does the suffix on 30234UUTG mean?
Suffix reading on 30234UUTG: the UUTG suffix marks the ULTAGE specification for large NTN tapered rollers — upgraded material and internal design for longer life inside the unchanged ISO 355 envelope; the suffix is part of the order number and the variants are not interchangeable articles.
Reviewed & verified by the MPN Base engineering desk against source catalog NTN Ball and Roller Bearings CAT.No.2203E on 2026-10-01. Read our editorial & correction policy.