33020U bearing: complete specifications & equivalents
The 33020U is a ISO 355 radial bearing sized 100 x 150 x 39 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | NTN |
| Bore diameter d | 100 mm |
| Outer diameter D | 150 mm |
| Width B | 39 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | steel |
| Basic dynamic load rating C | 248 kN |
| Basic static load rating C0 | 390 kN |
| Fatigue load limit Pu | 44.5 kN |
| Limiting speed (mechanical) | 2200 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 2400 g |
| Manufacturer designation | NTN 33020U |
| 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 | 3.937 in |
|---|---|
| Outer diameter D | 5.906 in |
| Width B | 1.535 in |
| ISO bore code | — |
| Radial section height (D−d)/2 | 25 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) | 18 of 24 |
| Bore above smallest 33000-series size | 75 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| 33020U | 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 33020U model number is decoded
The NTN 2203E table prints 33020U in the slim 33000 family: 100 mm bore, 150 mm cup OD, 39 mm T, with a grease limiting speed of 2,200 r/min and an oil-lubricated ceiling of 3,000 r/min. Reading the designation: the leading five digits follow the ISO 355 metric plan (dimension family plus two-digit bore code), and 33020U resolves to 100 mm bore; the NTN factory mark 4T is stamped on cone and cup but is a brand mark, not a size code, so the catalogue sku is printed without it. At 248 kN C the bearing offers about 2.5 kN of dynamic capacity per millimetre of the 100 mm bore — compare any substitution on this ratio and the 39 mm assembled T, not on bore alone. The two speed columns differ by a factor of .73 (grease/limiting 2,200 vs oil 3,000 r/min); heat generation at the cone rib decides which lubrication a real 33020U arrangement can sustain. Re-adjustment after bedding-in is standard practice: re-check end play once the paired 33020U arrangement has run in, because initial seat seating relaxes the set preload slightly.
Typical equipment & failure modes
Common applications
- marine winch and deck-machinery shafts
- paper-machine press-section rolls
- large agricultural and forestry machine axles
- heavy industrial gearboxes and crane travel drives
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 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
- Mount the 100 mm cone by induction heating (max 120 °C) and the cup with a press sleeve; the 2400 g ring mass makes cocking during fitting a direct raceway-brinelling risk.
- The thin 39 mm section of 33020U is built for low friction and tight envelopes, not the heavy preload of a 322/323 set; over-tightening adjustment on this 100 mm bore smears the roller ends against the rib.
- On slash-size and T-code bearings confirm the full code on both cone and cup before fitting: the 100 mm bore alone does not identify the cup, and a mismatched cone/cup set has no catalogue rating.
- Back-to-back and face-to-face arrangements react differently to shaft bending: pick the pair orientation for the moment load before locking the 100 mm shoulder geometry, because retrofitting flips the cups.
- Open 33020U units have no seals: a wheel-hub or gearbox application needs external sealing or the 2,200 r/min grease figure is meaningless once water reaches the cone rib.
- The 248/390 kN ratings and 44.5 kN Pu here are NTN Ball and Roller Bearings CAT.No.2203E figures for 33020U (ISO 355 2CE); 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 33020U?
33020U is a metric 4T tapered roller bearing to ISO 355: 100 mm bore, 150 mm outside diameter and 39 mm assembled width T (3.937 × 5.906 × 1.535 in). From NTN Ball and Roller Bearings CAT.No.2203E: C 248 kN, C0 390 kN, Pu 44.5 kN, grease limiting speed 2,200 r/min, oil speed 3,000 r/min, mass about 2400 g. It is an open, separable cone/cup bearing with a pressed-steel cage.
What does the 4T prefix mean on 33020U?
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 (33020U); the lower-case 4t- factory spelling of the code is retained among the search aliases.
How does the 33020U designation encode the 100 mm bore and what is 2CE?
last two digits 20 are the ISO bore code, ×5 = 100 mm (codes 00–03 use the 10/12/15/17 exception table). The 150 mm OD and 39 mm assembled T follow the ISO 355 dimension-series plan. 2CE 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 33020U list two speeds, 2,200 and 3,000 r/min?
The lower figure, 2,200 r/min, is the grease-lubricated limiting speed — the mechanical ceiling for the cage, rollers and cone-rib contact. With oil lubrication NTN rates 33020U at 3,000 r/min because oil removes rib-contact heat better. Real limits still depend on preload, oil flow and cooling.
What does the suffix on 33020U mean?
Suffix reading on 33020U: 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.