33118U bearing: complete specifications & equivalents
The 33118U is a ISO 355 radial bearing sized 90 x 150 x 45 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | NTN |
| Bore diameter d | 90 mm |
| Outer diameter D | 150 mm |
| Width B | 45 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | steel |
| Basic dynamic load rating C | 280 kN |
| Basic static load rating C0 | 400 kN |
| Fatigue load limit Pu | 46 kN |
| Limiting speed (mechanical) | 2400 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 3100 g |
| Manufacturer designation | NTN 33118U |
| 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 & 33100-series range
| Bore d | 3.543 in |
|---|---|
| Outer diameter D | 5.906 in |
| Width B | 1.772 in |
| ISO bore code | — |
| Radial section height (D−d)/2 | 30 mm |
| Smallest bore in 33100-series | 40 mm |
| Largest outer diameter in 33100-series | 200 mm |
| Width range across 33100-series | 26–62 mm |
| Bore position in 33100-series (smallest first) | 11 of 13 |
| Bore above smallest 33100-series size | 50 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| 33118U | 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 33118U model number is decoded
33118U is the NTN 4T catalogue entry for a 90×150×45 mm metric tapered roller bearing — separable cone and cup, designed for combined radial and axial load as an individually adjusted bearing. Reading the designation: the leading five digits follow the ISO 355 metric plan (dimension family plus two-digit bore code), and 33118U resolves to 90 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 280 kN C the bearing offers about 3.1 kN of dynamic capacity per millimetre of the 90 mm bore — compare any substitution on this ratio and the 45 mm assembled T, not on bore alone. The 3.1 kN-per-mm-bore capacity figure for 33118U summarises the 280 kN rating over 90 mm bore; use it to sanity-check an interchange candidate before swapping brands. With a rotating shaft a k5/m5 shaft seat and a press-fit cup are typical catalogue practice for 33118U; reverse the logic if the cup rotates, and re-verify against load direction and magnitude.
Typical equipment & failure modes
Common applications
- large agricultural and forestry machine axles
- heavy industrial gearboxes and crane travel drives
- rolling-mill auxiliary and pinion-stand shafts
- large conveyor and bucket-elevator pulleys
Known failure patterns
- cone-raceway spalling at the large rib when preload is set too high for the lubricant film
- 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 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
- Mount the 90 mm cone by induction heating (max 120 °C) and the cup with a press sleeve; the 3100 g ring mass makes cocking during fitting a direct raceway-brinelling risk.
- The light-wide 33100 family at 90 mm bore (150×45 mm assembled) carries more capacity than the lighter 320/329 sections but generates more preload heat; confirm oil availability before running near the 3,200 r/min oil ceiling.
- On slash-size and T-code bearings confirm the full code on both cone and cup before fitting: the 90 mm bore alone does not identify the cup, and a mismatched cone/cup set has no catalogue rating.
- Do not confuse T (45 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.
- Open 33118U units have no seals: a wheel-hub or gearbox application needs external sealing or the 2,400 r/min grease figure is meaningless once water reaches the cone rib.
- The 280/400 kN ratings and 46 kN Pu here are NTN Ball and Roller Bearings CAT.No.2203E figures for 33118U (ISO 355 3DE); 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 33118U?
33118U is a metric 4T tapered roller bearing to ISO 355: 90 mm bore, 150 mm outside diameter and 45 mm assembled width T (3.543 × 5.906 × 1.772 in). From NTN Ball and Roller Bearings CAT.No.2203E: C 280 kN, C0 400 kN, Pu 46 kN, grease limiting speed 2,400 r/min, oil speed 3,200 r/min, mass about 3100 g. It is an open, separable cone/cup bearing with a pressed-steel cage.
What does the 4T prefix mean on 33118U?
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 (33118U); the lower-case 4t- factory spelling of the code is retained among the search aliases.
How does the 33118U designation encode the 90 mm bore and what is 3DE?
last two digits 18 are the ISO bore code, ×5 = 90 mm (codes 00–03 use the 10/12/15/17 exception table). The 150 mm OD and 45 mm assembled T follow the ISO 355 dimension-series plan. 3DE 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 33118U list two speeds, 2,400 and 3,200 r/min?
The lower figure, 2,400 r/min, is the grease-lubricated limiting speed — the mechanical ceiling for the cage, rollers and cone-rib contact. With oil lubrication NTN rates 33118U at 3,200 r/min because oil removes rib-contact heat better. Real limits still depend on preload, oil flow and cooling.
What does the suffix on 33118U mean?
Suffix reading on 33118U: 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.