30340UTG bearing: complete specifications & equivalents
The 30340UTG is a ISO 355 radial bearing sized 200 x 420 x 89 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | NTN |
| Bore diameter d | 200 mm |
| Outer diameter D | 420 mm |
| Width B | 89 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | steel |
| Basic dynamic load rating C | 1340 kN |
| Basic static load rating C0 | 1370 kN |
| Fatigue load limit Pu | 119 kN |
| Limiting speed (mechanical) | 850 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 51500 g |
| Manufacturer designation | NTN 30340UTG |
| 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 | 7.874 in |
|---|---|
| Outer diameter D | 16.535 in |
| Width B | 3.504 in |
| ISO bore code | — |
| Radial section height (D−d)/2 | 110 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) | 30 of 32 |
| Bore above smallest 30300-series size | 185 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| 30340UTG | 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 30340UTG model number is decoded
For a 200 mm shaft with a thrust component, NTN lists 30340UTG, a metric 4T tapered roller bearing of 1340 kN C and 1370 kN C0 inside the 420 mm OD, 89 mm-wide assembled set. NTN also quotes this bearing with its ISO 355 dimension-series abbreviation which is the maker-neutral cross-reference for the 200×420 mm envelope; 4T is NTN's own tapered-roller brand mark on the parts. The rollers run with their large ends against the cone's integral guide rib; the rib/end-flange contact carries the thrust component and is the reason lubricant must reach the rib face of 30340UTG, not only the raceway. The 6.7 kN-per-mm-bore capacity figure for 30340UTG summarises the 1340 kN rating over 200 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 200 mm pair is misadjusted and the 89 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
- cone-raceway spalling at the large rib when preload is set too high for the lubricant film
- rib scoring when axial load is carried beyond the cone rib capacity of the adjusted pair
- preload loss from racewear when one bearing of the paired set is replaced without re-adjusting end play
- cage fatigue when the pair is run continuously near the grease limiting speed without oil cooling
- water-induced pitting when the open bearing is exposed to washdown without external seals
Selection pitfalls — read before you substitute
- At 200 mm bore the 30340UTG 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 1340 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 200 mm bore; do not swap to the lighter family without re-checking the 850 r/min grease limit and the thrust load split.
- Open 30340UTG units have no seals: a wheel-hub or gearbox application needs external sealing or the 850 r/min grease figure is meaningless once water reaches the cone rib.
- Do not confuse T (89 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.
- Back-to-back and face-to-face arrangements react differently to shaft bending: pick the pair orientation for the moment load before locking the 200 mm shoulder geometry, because retrofitting flips the cups.
- The 1340/1370 kN ratings and 119 kN Pu here are NTN Ball and Roller Bearings CAT.No.2203E figures for 30340UTG; 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 30340UTG?
30340UTG is a metric 4T tapered roller bearing to ISO 355: 200 mm bore, 420 mm outside diameter and 89 mm assembled width T (7.874 × 16.535 × 3.504 in). From NTN Ball and Roller Bearings CAT.No.2203E: C 1340 kN, C0 1370 kN, Pu 119 kN, grease limiting speed 850 r/min, oil speed 1,200 r/min, mass about 51500 g. It is an open, separable cone/cup bearing with a pressed-steel cage.
What does the 4T prefix mean on 30340UTG?
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 (30340UTG); the lower-case 4t- factory spelling of the code is retained among the search aliases.
How does the 30340UTG designation encode the 200 mm bore?
last two digits 40 are the ISO bore code, ×5 = 200 mm (codes 00–03 use the 10/12/15/17 exception table). The 420 mm OD and 89 mm assembled T follow the ISO 355 dimension-series plan.
Why does 30340UTG list two speeds, 850 and 1,200 r/min?
The lower figure, 850 r/min, is the grease-lubricated limiting speed — the mechanical ceiling for the cage, rollers and cone-rib contact. With oil lubrication NTN rates 30340UTG at 1,200 r/min because oil removes rib-contact heat better. Real limits still depend on preload, oil flow and cooling.
What does the suffix on 30340UTG mean?
Suffix reading on 30340UTG: the UTG 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.