33028U bearing: complete specifications & equivalents
The 33028U is a ISO 355 radial bearing sized 140 x 210 x 56 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | NTN |
| Bore diameter d | 140 mm |
| Outer diameter D | 210 mm |
| Width B | 56 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | steel |
| Basic dynamic load rating C | 435 kN |
| Basic static load rating C0 | 715 kN |
| Fatigue load limit Pu | 74 kN |
| Limiting speed (mechanical) | 1600 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 6590 g |
| Manufacturer designation | NTN 33028U |
| 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 | 5.512 in |
|---|---|
| Outer diameter D | 8.268 in |
| Width B | 2.205 in |
| ISO bore code | — |
| Radial section height (D−d)/2 | 35 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) | 23 of 24 |
| Bore above smallest 33000-series size | 115 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| 33028U | 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 33028U model number is decoded
33028U is a metric single-row tapered roller bearing in the NTN 4T programme: a pressed-steel cage guides profiled rollers between a separable cone and cup on the 140×210 mm ISO 355 envelope, with 56 mm overall assembled width T. On the NTN nameplate the parts carry 4T plus the bare code, while 2203E orders 33028U by the metric ISO 355 number (ISO series abbreviation 2DE): 140 mm bore, 210 mm OD. A tapered roller bearing reacts combined radial and one-direction axial load; NTN mounts 33028U cone and cup separately and adjusts end play or preload against a second bearing, so the arrangement locates the shaft in both directions. Imperial cross-check for the drawing: 140×210×56 mm is 5.512 × 8.268 × 2.205 in; ISO 355 makes the envelope interchangeable but C/C0, 435/715 kN, is NTN-specific. With a rotating shaft a m6/n6 shaft seat and a press-fit cup are typical catalogue practice for 33028U; reverse the logic if the cup rotates, and re-verify against load direction and magnitude.
Typical equipment & failure modes
Common applications
- large marine propulsion reduction gears
- cement-plant kiln and mill drive trains
- rolling-mill roll-neck and gearbox positions
- large crusher and SAG/AG-mill drive shafts
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
- 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 140 mm bore the 33028U 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 435 kN C level.
- The thin 56 mm section of 33028U is built for low friction and tight envelopes, not the heavy preload of a 322/323 set; over-tightening adjustment on this 140 mm bore smears the roller ends against the rib.
- Grease packs must leave free volume in the 56 mm-wide set; over-greasing a paired bearing churning at the 2,100 r/min oil-band speed raises temperature and destroys the preload setting.
- Grease packs must leave free volume in the 56 mm-wide set; over-greasing a paired bearing churning at the 2,100 r/min oil-band speed raises temperature and destroys the preload setting.
- Do not confuse T (56 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 435/715 kN ratings and 74 kN Pu here are NTN Ball and Roller Bearings CAT.No.2203E figures for 33028U (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 33028U?
33028U is a metric 4T tapered roller bearing to ISO 355: 140 mm bore, 210 mm outside diameter and 56 mm assembled width T (5.512 × 8.268 × 2.205 in). From NTN Ball and Roller Bearings CAT.No.2203E: C 435 kN, C0 715 kN, Pu 74 kN, grease limiting speed 1,600 r/min, oil speed 2,100 r/min, mass about 6590 g. It is an open, separable cone/cup bearing with a pressed-steel cage.
What does the 4T prefix mean on 33028U?
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 (33028U); the lower-case 4t- factory spelling of the code is retained among the search aliases.
How does the 33028U designation encode the 140 mm bore and what is 2DE?
last two digits 28 are the ISO bore code, ×5 = 140 mm (codes 00–03 use the 10/12/15/17 exception table). The 210 mm OD and 56 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 33028U list two speeds, 1,600 and 2,100 r/min?
The lower figure, 1,600 r/min, is the grease-lubricated limiting speed — the mechanical ceiling for the cage, rollers and cone-rib contact. With oil lubrication NTN rates 33028U at 2,100 r/min because oil removes rib-contact heat better. Real limits still depend on preload, oil flow and cooling.
What does the suffix on 33028U mean?
Suffix reading on 33028U: 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.