33024U bearing: complete specifications & equivalents
The 33024U is a ISO 355 radial bearing sized 120 x 180 x 48 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 | 180 mm |
| Width B | 48 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | steel |
| Basic dynamic load rating C | 325 kN |
| Basic static load rating C0 | 520 kN |
| Fatigue load limit Pu | 56.5 kN |
| Limiting speed (mechanical) | 1800 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 4140 g |
| Manufacturer designation | NTN 33024U |
| 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 & 33000-series range
| Bore d | 4.724 in |
|---|---|
| Outer diameter D | 7.087 in |
| Width B | 1.89 in |
| ISO bore code | — |
| Radial section height (D−d)/2 | 30 mm |
| Smallest bore in 33000-series | 25 mm |
| Largest outer diameter in 33000-series | 225 mm |
| Width range across 33000-series | 17–59 mm |
| Bore position in 33000-series (smallest first) | 21 of 24 |
| Bore above smallest 33000-series size | 95 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| 33024U | 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 33024U model number is decoded
NTN supplies this 120 mm bore tapered roller position as 33024U: one cone assembly, one cup, line-contact rollers and a steel cage, rated 325 kN basic dynamic and 520 kN static on the slim 33000 family. NTN also quotes this bearing with its ISO 355 dimension-series abbreviation, 2DE, which is the maker-neutral cross-reference for the 120×180 mm envelope; 4T is NTN's own tapered-roller brand mark on the parts. Suffix reading on 33024U: 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. Catalogue mass of the 33024U set is 4140 g (0.163 lb cone + cup); abutment and shaft shoulder design must carry that mass square to the axis. 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 33024U.
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
- cone-raceway spalling at the large rib when preload is set too high for the lubricant film
- preload loss from racewear when one bearing of the paired set is replaced without re-adjusting end play
- rib scoring when axial load is carried beyond the cone rib capacity of the adjusted pair
- cage damage from a mounting blow delivered through the roller complement instead of the ring face
- water-induced pitting when the open bearing is exposed to washdown without external seals
Selection pitfalls — read before you substitute
- At 120 mm bore the 33024U 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 325 kN C level.
- The thin 48 mm section of 33024U is built for low friction and tight envelopes, not the heavy preload of a 322/323 set; over-tightening adjustment on this 120 mm bore smears the roller ends against the rib.
- The U/UTG/X/C/CA/D suffix variants of a base number share the bore but not the article: ordering 33024U by size alone can deliver the wrong contact-angle execution for a pinion position.
- Replacing one half of an adjusted pair without resetting end play negates the 48 mm T dimension logic: re-adjust the set and re-verify the contact pattern rather than reusing the old spacer stack.
- ISO 355 makes the 120×180 mm envelope interchangeable but not the ratings: NTN prints 325/520 kN for this execution, and a cheaper same-number part can differ in roller complement and steel.
- The 325/520 kN ratings and 56.5 kN Pu here are NTN Ball and Roller Bearings CAT.No.2203E figures for 33024U (ISO 355 2DE); 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 33024U?
33024U is a metric 4T tapered roller bearing to ISO 355: 120 mm bore, 180 mm outside diameter and 48 mm assembled width T (4.724 × 7.087 × 1.89 in). From NTN Ball and Roller Bearings CAT.No.2203E: C 325 kN, C0 520 kN, Pu 56.5 kN, grease limiting speed 1,800 r/min, oil speed 2,500 r/min, mass about 4140 g. It is an open, separable cone/cup bearing with a pressed-steel cage.
What does the 4T prefix mean on 33024U?
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 (33024U); the lower-case 4t- factory spelling of the code is retained among the search aliases.
How does the 33024U designation encode the 120 mm bore and what is 2DE?
last two digits 24 are the ISO bore code, ×5 = 120 mm (codes 00–03 use the 10/12/15/17 exception table). The 180 mm OD and 48 mm assembled T follow the ISO 355 dimension-series plan. 2DE 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 33024U list two speeds, 1,800 and 2,500 r/min?
The lower figure, 1,800 r/min, is the grease-lubricated limiting speed — the mechanical ceiling for the cage, rollers and cone-rib contact. With oil lubrication NTN rates 33024U at 2,500 r/min because oil removes rib-contact heat better. Real limits still depend on preload, oil flow and cooling.
What does the suffix on 33024U mean?
Suffix reading on 33024U: 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.