30218U bearing: complete specifications & equivalents
The 30218U is a ISO 355 radial bearing sized 90 x 160 x 32.5 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 | 160 mm |
| Width B | 32.5 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | steel |
| Basic dynamic load rating C | 230 kN |
| Basic static load rating C0 | 267 kN |
| Fatigue load limit Pu | 30.5 kN |
| Limiting speed (mechanical) | 2200 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 2660 g |
| Manufacturer designation | NTN 30218U |
| 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 | 3.543 in |
|---|---|
| Outer diameter D | 6.299 in |
| Width B | 1.28 in |
| ISO bore code | — |
| Radial section height (D−d)/2 | 35 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) | 18 of 37 |
| Bore above smallest 30200-series size | 75 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| 30218U | 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 30218U model number is decoded
NTN supplies this 90 mm bore tapered roller position as 30218U: one cone assembly, one cup, line-contact rollers and a steel cage, rated 230 kN basic dynamic and 267 kN static on the standard-section 30200 family. The last two digits 18 are the ISO bore code, ×5 = 90 mm (codes 00–03 use the 10/12/15/17 exception table) under the ISO 355 numbering; the 32.5 mm value printed here is T, the width of the fully assembled cone-plus-cup set, not the inner-ring width alone. Suffix reading on 30218U: 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. The fatigue load limit Pu printed for 30218U is 30.5 kN; in the adjusted-life equation that is the equivalent-load floor below which high reliability is expected even under contamination. With a rotating shaft a k5/m5 shaft seat and a press-fit cup are typical catalogue practice for 30218U; 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
- flaking on one cone only when a back-to-back / face-to-face pair is loaded unevenly by a bent shaft
- smearing on the roller large ends and cone rib after a dry start with preload but no oil film
- pressed-steel cage pocket wear from roller skid at light radial load and high speed
- fretting corrosion on a loose cone seat that creeps under rotating load
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 2660 g ring mass makes cocking during fitting a direct raceway-brinelling risk.
- The standard-section 30200 family at 90 mm bore (160×32.5 mm assembled) carries more capacity than the lighter 320/329 sections but generates more preload heat; confirm oil availability before running near the 3,000 r/min oil ceiling.
- Minimum load matters at high speed: an unloaded 30218U at a large fraction of 2,200 r/min lets rollers skid and smear the cone rib; spring-preload lightly loaded pair arrangements.
- Never fit the 90 mm cone by hammering the 160 mm cup: force for both press fits goes through the ring faces only, or brinell marks release as noise within the first running hours.
- ISO 355 makes the 90×160 mm envelope interchangeable but not the ratings: NTN prints 230/267 kN for this execution, and a cheaper same-number part can differ in roller complement and steel.
- The 230/267 kN ratings and 30.5 kN Pu here are NTN Ball and Roller Bearings CAT.No.2203E figures for 30218U (ISO 355 3FB); 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 30218U?
30218U is a metric 4T tapered roller bearing to ISO 355: 90 mm bore, 160 mm outside diameter and 32.5 mm assembled width T (3.543 × 6.299 × 1.28 in). From NTN Ball and Roller Bearings CAT.No.2203E: C 230 kN, C0 267 kN, Pu 30.5 kN, grease limiting speed 2,200 r/min, oil speed 3,000 r/min, mass about 2660 g. It is an open, separable cone/cup bearing with a pressed-steel cage.
What does the 4T prefix mean on 30218U?
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 (30218U); the lower-case 4t- factory spelling of the code is retained among the search aliases.
How does the 30218U designation encode the 90 mm bore and what is 3FB?
last two digits 18 are the ISO bore code, ×5 = 90 mm (codes 00–03 use the 10/12/15/17 exception table). The 160 mm OD and 32.5 mm assembled T follow the ISO 355 dimension-series plan. 3FB 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 30218U 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 30218U 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 30218U mean?
Suffix reading on 30218U: 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.