30334UUTG bearing: complete specifications & equivalents
The 30334UUTG is a ISO 355 radial bearing sized 170 x 360 x 80 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 | 360 mm |
| Width B | 80 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | steel |
| Basic dynamic load rating C | 1290 kN |
| Basic static load rating C0 | 1320 kN |
| Fatigue load limit Pu | 120 kN |
| Limiting speed (mechanical) | 1000 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 35200 g |
| Manufacturer designation | NTN 30334UUTG |
| 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 & 30300-series range
| Bore d | 6.693 in |
|---|---|
| Outer diameter D | 14.173 in |
| Width B | 3.15 in |
| ISO bore code | — |
| Radial section height (D−d)/2 | 95 mm |
| Smallest bore in 30300-series | 15 mm |
| Largest outer diameter in 30300-series | 500 mm |
| Width range across 30300-series | 14.25–105 mm |
| Bore position in 30300-series (smallest first) | 27 of 32 |
| Bore above smallest 30300-series size | 155 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| 30334UUTG | 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 30334UUTG model number is decoded
30334UUTG is a metric single-row tapered roller bearing in the NTN 4T programme: a pressed-steel cage guides profiled rollers between a separable cone and cup on the 170×360 mm ISO 355 envelope, with 80 mm overall assembled width T. On the NTN nameplate the parts carry 4T plus the bare code, while 2203E orders 30334UUTG by the metric ISO 355 number (ISO series abbreviation 2GB): 170 mm bore, 360 mm OD. The pressed-steel cage and surface-finished roller ends are standard 4T execution; ULTAGE-marked variants use upgraded material and internal geometry aimed at longer rating life with the same ISO 355 envelope. The 7.6 kN-per-mm-bore capacity figure for 30334UUTG summarises the 1290 kN rating over 170 mm bore; use it to sanity-check an interchange candidate before swapping brands. 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 80 mm T set will edge-load in service.
Typical equipment & failure modes
Common applications
- heavy haul railway traction gearboxes
- large marine propulsion reduction gears
- cement-plant kiln and mill drive trains
- rolling-mill roll-neck and gearbox positions
Known failure patterns
- cone-raceway spalling at the large rib when preload is set too high for the lubricant film
- smearing on the roller large ends and cone rib after a dry start with preload but no oil film
- flaking on one cone only when a back-to-back / face-to-face pair is loaded unevenly by a bent shaft
- cage damage from a mounting blow delivered through the roller complement instead of the ring face
- edge loading when shaft deflection exceeds the few arc-minutes of misalignment the adjusted pair allows
Selection pitfalls — read before you substitute
- At 170 mm bore the 30334UUTG 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 1290 kN C level.
- The steeper contact angle of the large-OD 30300 family with the steeper contact angle raises axial capacity but lowers the speed ceiling against a 302/322 bearing at 170 mm bore; do not swap to the lighter family without re-checking the 1,000 r/min grease limit and the thrust load split.
- Grease packs must leave free volume in the 80 mm-wide set; over-greasing a paired bearing churning at the 1,500 r/min oil-band speed raises temperature and destroys the preload setting.
- Open 30334UUTG units have no seals: a wheel-hub or gearbox application needs external sealing or the 1,000 r/min grease figure is meaningless once water reaches the cone rib.
- Replacing one half of an adjusted pair without resetting end play negates the 80 mm T dimension logic: re-adjust the set and re-verify the contact pattern rather than reusing the old spacer stack.
- The 1290/1320 kN ratings and 120 kN Pu here are NTN Ball and Roller Bearings CAT.No.2203E figures for 30334UUTG (ISO 355 2GB); 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 30334UUTG?
30334UUTG is a metric 4T tapered roller bearing to ISO 355: 170 mm bore, 360 mm outside diameter and 80 mm assembled width T (6.693 × 14.173 × 3.15 in). From NTN Ball and Roller Bearings CAT.No.2203E: C 1290 kN, C0 1320 kN, Pu 120 kN, grease limiting speed 1,000 r/min, oil speed 1,500 r/min, mass about 35200 g. It is an open, separable cone/cup bearing with a pressed-steel cage.
What does the 4T prefix mean on 30334UUTG?
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 (30334UUTG); the lower-case 4t- factory spelling of the code is retained among the search aliases.
How does the 30334UUTG designation encode the 170 mm bore and what is 2GB?
last two digits 34 are the ISO bore code, ×5 = 170 mm (codes 00–03 use the 10/12/15/17 exception table). The 360 mm OD and 80 mm assembled T follow the ISO 355 dimension-series plan. 2GB 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 30334UUTG list two speeds, 1,000 and 1,500 r/min?
The lower figure, 1,000 r/min, is the grease-lubricated limiting speed — the mechanical ceiling for the cage, rollers and cone-rib contact. With oil lubrication NTN rates 30334UUTG at 1,500 r/min because oil removes rib-contact heat better. Real limits still depend on preload, oil flow and cooling.
What does the suffix on 30334UUTG mean?
Suffix reading on 30334UUTG: 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.