30230U bearing: complete specifications & equivalents
The 30230U is a ISO 355 radial bearing sized 150 x 270 x 49 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | NTN |
| Bore diameter d | 150 mm |
| Outer diameter D | 270 mm |
| Width B | 49 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | steel |
| Basic dynamic load rating C | 500 kN |
| Basic static load rating C0 | 605 kN |
| Fatigue load limit Pu | 59 kN |
| Limiting speed (mechanical) | 1300 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 11000 g |
| Manufacturer designation | NTN 30230U |
| 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 | 5.906 in |
|---|---|
| Outer diameter D | 10.63 in |
| Width B | 1.929 in |
| ISO bore code | — |
| Radial section height (D−d)/2 | 60 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) | 26 of 37 |
| Bore above smallest 30200-series size | 135 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| 30230U | 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 30230U model number is decoded
30230U is the NTN 4T catalogue entry for a 150×270×49 mm metric tapered roller bearing — separable cone and cup, designed for combined radial and axial load as an individually adjusted bearing. The last two digits 30 are the ISO bore code, ×5 = 150 mm (codes 00–03 use the 10/12/15/17 exception table) under the ISO 355 numbering; the 49 mm value printed here is T, the width of the fully assembled cone-plus-cup set, not the inner-ring width alone. 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 30230U, not only the raceway. The two speed columns differ by a factor of .76 (grease/limiting 1,300 vs oil 1,700 r/min); heat generation at the cone rib decides which lubrication a real 30230U arrangement can sustain. Open 4T bearings need application seals; without them the grease at the cone rib of 30230U washes out and the rib/roller-end contact smears on the first wet or dusty shift.
Typical equipment & failure modes
Common applications
- large crusher and SAG/AG-mill drive shafts
- wind-turbine gearbox and main-shaft arrangements
- offshore crane and drawworks drums
- heavy haul railway traction gearboxes
Known failure patterns
- cup creep and housing fretting when the specified outer-ring press fit is not achieved
- 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 fatigue when the pair is run continuously near the grease limiting speed without oil cooling
- indentation of the raceways by hard particles in unsealed open arrangements
Selection pitfalls — read before you substitute
- At 150 mm bore the 30230U 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 500 kN C level.
- The standard-section 30200 family at 150 mm bore (270×49 mm assembled) carries more capacity than the lighter 320/329 sections but generates more preload heat; confirm oil availability before running near the 1,700 r/min oil ceiling.
- Open 30230U units have no seals: a wheel-hub or gearbox application needs external sealing or the 1,300 r/min grease figure is meaningless once water reaches the cone rib.
- Never fit the 150 mm cone by hammering the 270 mm cup: force for both press fits goes through the ring faces only, or brinell marks release as noise within the first running hours.
- Back-to-back and face-to-face arrangements react differently to shaft bending: pick the pair orientation for the moment load before locking the 150 mm shoulder geometry, because retrofitting flips the cups.
- The 500/605 kN ratings and 59 kN Pu here are NTN Ball and Roller Bearings CAT.No.2203E figures for 30230U (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 30230U?
30230U is a metric 4T tapered roller bearing to ISO 355: 150 mm bore, 270 mm outside diameter and 49 mm assembled width T (5.906 × 10.63 × 1.929 in). From NTN Ball and Roller Bearings CAT.No.2203E: C 500 kN, C0 605 kN, Pu 59 kN, grease limiting speed 1,300 r/min, oil speed 1,700 r/min, mass about 11000 g. It is an open, separable cone/cup bearing with a pressed-steel cage.
What does the 4T prefix mean on 30230U?
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 (30230U); the lower-case 4t- factory spelling of the code is retained among the search aliases.
How does the 30230U designation encode the 150 mm bore and what is 4GB?
last two digits 30 are the ISO bore code, ×5 = 150 mm (codes 00–03 use the 10/12/15/17 exception table). The 270 mm OD and 49 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 30230U list two speeds, 1,300 and 1,700 r/min?
The lower figure, 1,300 r/min, is the grease-lubricated limiting speed — the mechanical ceiling for the cage, rollers and cone-rib contact. With oil lubrication NTN rates 30230U at 1,700 r/min because oil removes rib-contact heat better. Real limits still depend on preload, oil flow and cooling.
What does the suffix on 30230U mean?
Suffix reading on 30230U: U marks the reinforced/uprated internal design of the bare number, a separate order number with higher load capacity than the basic execution; 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.