30338UTG bearing: complete specifications & equivalents
The 30338UTG is a ISO 355 radial bearing sized 190 x 400 x 86 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | NTN |
| Bore diameter d | 190 mm |
| Outer diameter D | 400 mm |
| Width B | 86 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | steel |
| Basic dynamic load rating C | 1200 kN |
| Basic static load rating C0 | 1200 kN |
| Fatigue load limit Pu | 106 kN |
| Limiting speed (mechanical) | 900 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 43600 g |
| Manufacturer designation | NTN 30338UTG |
| 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 | 7.48 in |
|---|---|
| Outer diameter D | 15.748 in |
| Width B | 3.386 in |
| ISO bore code | — |
| Radial section height (D−d)/2 | 105 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) | 29 of 32 |
| Bore above smallest 30300-series size | 175 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| 30338UTG | 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 30338UTG model number is decoded
NTN supplies this 190 mm bore tapered roller position as 30338UTG: one cone assembly, one cup, line-contact rollers and a steel cage, rated 1200 kN basic dynamic and 1200 kN static on the large-OD 30300 family with the steeper contact angle. NTN also quotes this bearing with its ISO 355 dimension-series abbreviation which is the maker-neutral cross-reference for the 190×400 mm envelope; 4T is NTN's own tapered-roller brand mark on the parts. A tapered roller bearing reacts combined radial and one-direction axial load; NTN mounts 30338UTG cone and cup separately and adjusts end play or preload against a second bearing, so the arrangement locates the shaft in both directions. The 6.3 kN-per-mm-bore capacity figure for 30338UTG summarises the 1200 kN rating over 190 mm bore; use it to sanity-check an interchange candidate before swapping brands. Open 4T bearings need application seals; without them the grease at the cone rib of 30338UTG washes out and the rib/roller-end contact smears on the first wet or dusty shift.
Typical equipment & failure modes
Common applications
- wind-turbine gearbox and main-shaft arrangements
- offshore crane and drawworks drums
- heavy haul railway traction gearboxes
- large marine propulsion reduction gears
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
- pressed-steel cage pocket wear from roller skid at light radial load and high speed
- edge loading when shaft deflection exceeds the few arc-minutes of misalignment the adjusted pair allows
Selection pitfalls — read before you substitute
- At 190 mm bore the 30338UTG 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 1200 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 190 mm bore; do not swap to the lighter family without re-checking the 900 r/min grease limit and the thrust load split.
- Never fit the 190 mm cone by hammering the 400 mm cup: force for both press fits goes through the ring faces only, or brinell marks release as noise within the first running hours.
- On slash-size and T-code bearings confirm the full code on both cone and cup before fitting: the 190 mm bore alone does not identify the cup, and a mismatched cone/cup set has no catalogue rating.
- Do not confuse T (86 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 1200/1200 kN ratings and 106 kN Pu here are NTN Ball and Roller Bearings CAT.No.2203E figures for 30338UTG; 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 30338UTG?
30338UTG is a metric 4T tapered roller bearing to ISO 355: 190 mm bore, 400 mm outside diameter and 86 mm assembled width T (7.48 × 15.748 × 3.386 in). From NTN Ball and Roller Bearings CAT.No.2203E: C 1200 kN, C0 1200 kN, Pu 106 kN, grease limiting speed 900 r/min, oil speed 1,300 r/min, mass about 43600 g. It is an open, separable cone/cup bearing with a pressed-steel cage.
What does the 4T prefix mean on 30338UTG?
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 (30338UTG); the lower-case 4t- factory spelling of the code is retained among the search aliases.
How does the 30338UTG designation encode the 190 mm bore?
last two digits 38 are the ISO bore code, ×5 = 190 mm (codes 00–03 use the 10/12/15/17 exception table). The 400 mm OD and 86 mm assembled T follow the ISO 355 dimension-series plan.
Why does 30338UTG list two speeds, 900 and 1,300 r/min?
The lower figure, 900 r/min, is the grease-lubricated limiting speed — the mechanical ceiling for the cage, rollers and cone-rib contact. With oil lubrication NTN rates 30338UTG at 1,300 r/min because oil removes rib-contact heat better. Real limits still depend on preload, oil flow and cooling.
What does the suffix on 30338UTG mean?
Suffix reading on 30338UTG: 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.