30224U bearing: complete specifications & equivalents
The 30224U is a ISO 355 radial bearing sized 120 x 215 x 43.5 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | NTN |
| Bore diameter d | 120 mm |
| Outer diameter D | 215 mm |
| Width B | 43.5 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | steel |
| Basic dynamic load rating C | 385 kN |
| Basic static load rating C0 | 470 kN |
| Fatigue load limit Pu | 49 kN |
| Limiting speed (mechanical) | 1700 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 6320 g |
| Manufacturer designation | NTN 30224U |
| 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 | 4.724 in |
|---|---|
| Outer diameter D | 8.465 in |
| Width B | 1.713 in |
| ISO bore code | — |
| Radial section height (D−d)/2 | 47.5 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) | 23 of 37 |
| Bore above smallest 30200-series size | 105 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| 30224U | 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 30224U model number is decoded
30224U 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. NTN also quotes this bearing with its ISO 355 dimension-series abbreviation, 4FB, which is the maker-neutral cross-reference for the 120×215 mm envelope; 4T is NTN's own tapered-roller brand mark on the parts. 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 fatigue load limit Pu printed for 30224U is 49 kN; in the adjusted-life equation that is the equivalent-load floor below which high reliability is expected even under contamination. Mount the 120 mm-bore cone on the shaft first (induction heat, max 120 °C), fit the cup square in its housing, then set preload or end play; never drive the cup home through the rollers of 30224U.
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
- 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
- false brinelling on a stationary paired set exposed to external vibration
Selection pitfalls — read before you substitute
- At 120 mm bore the 30224U 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 385 kN C level.
- The standard-section 30200 family at 120 mm bore (215×43.5 mm assembled) carries more capacity than the lighter 320/329 sections but generates more preload heat; confirm oil availability before running near the 2,200 r/min oil ceiling.
- Minimum load matters at high speed: an unloaded 30224U at a large fraction of 1,700 r/min lets rollers skid and smear the cone rib; spring-preload lightly loaded pair arrangements.
- Back-to-back and face-to-face arrangements react differently to shaft bending: pick the pair orientation for the moment load before locking the 120 mm shoulder geometry, because retrofitting flips the cups.
- Replacing one half of an adjusted pair without resetting end play negates the 43.5 mm T dimension logic: re-adjust the set and re-verify the contact pattern rather than reusing the old spacer stack.
- The 385/470 kN ratings and 49 kN Pu here are NTN Ball and Roller Bearings CAT.No.2203E figures for 30224U (ISO 355 4FB); 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 30224U?
30224U is a metric 4T tapered roller bearing to ISO 355: 120 mm bore, 215 mm outside diameter and 43.5 mm assembled width T (4.724 × 8.465 × 1.713 in). From NTN Ball and Roller Bearings CAT.No.2203E: C 385 kN, C0 470 kN, Pu 49 kN, grease limiting speed 1,700 r/min, oil speed 2,200 r/min, mass about 6320 g. It is an open, separable cone/cup bearing with a pressed-steel cage.
What does the 4T prefix mean on 30224U?
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 (30224U); the lower-case 4t- factory spelling of the code is retained among the search aliases.
How does the 30224U designation encode the 120 mm bore and what is 4FB?
last two digits 24 are the ISO bore code, ×5 = 120 mm (codes 00–03 use the 10/12/15/17 exception table). The 215 mm OD and 43.5 mm assembled T follow the ISO 355 dimension-series plan. 4FB 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 30224U list two speeds, 1,700 and 2,200 r/min?
The lower figure, 1,700 r/min, is the grease-lubricated limiting speed — the mechanical ceiling for the cage, rollers and cone-rib contact. With oil lubrication NTN rates 30224U at 2,200 r/min because oil removes rib-contact heat better. Real limits still depend on preload, oil flow and cooling.
What does the suffix on 30224U mean?
Suffix reading on 30224U: 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.