30217U bearing: complete specifications & equivalents
The 30217U is a ISO 355 radial bearing sized 85 x 150 x 30.5 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | NTN |
| Bore diameter d | 85 mm |
| Outer diameter D | 150 mm |
| Width B | 30.5 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | steel |
| Basic dynamic load rating C | 203 kN |
| Basic static load rating C0 | 232 kN |
| Fatigue load limit Pu | 27 kN |
| Limiting speed (mechanical) | 2400 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 2130 g |
| Manufacturer designation | NTN 30217U |
| 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 | 3.346 in |
|---|---|
| Outer diameter D | 5.906 in |
| Width B | 1.201 in |
| ISO bore code | — |
| Radial section height (D−d)/2 | 32.5 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) | 17 of 37 |
| Bore above smallest 30200-series size | 70 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| 30217U | 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 30217U model number is decoded
30217U belongs to the NTN metric 4T tapered roller range (standard-section 30200 family); the open bearing leaves sealing to the application and is normally ordered and mounted as an adjustable matched pair. Reading the designation: the leading five digits follow the ISO 355 metric plan (dimension family plus two-digit bore code), and 30217U resolves to 85 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. Individually mounted, 30217U takes axial force in one direction only; two bearings are arranged face-to-face (X) or back-to-back (O) according to the moment stiffness and misalignment the shaft requires. Speed planning uses both catalogue columns: grease 2,400 r/min is the cage/rib mechanical ceiling for 30217U, oil 3,200 r/min is available with circulating oil — a 800 r/min margin at this size. Re-adjustment after bedding-in is standard practice: re-check end play once the paired 30217U arrangement has run in, because initial seat seating relaxes the set preload slightly.
Typical equipment & failure modes
Common applications
- paper-machine press-section rolls
- large agricultural and forestry machine axles
- heavy industrial gearboxes and crane travel drives
- rolling-mill auxiliary and pinion-stand shafts
Known failure patterns
- cup creep and housing fretting when the specified outer-ring press fit is not achieved
- rib scoring when axial load is carried beyond the cone rib capacity of the adjusted pair
- preload loss from racewear when one bearing of the paired set is replaced without re-adjusting end play
- cage damage from a mounting blow delivered through the roller complement instead of the ring face
- brinell marks on cone and cup raceways from impact during handling or hammering during fitting
Selection pitfalls — read before you substitute
- Mount the 85 mm cone by induction heating (max 120 °C) and the cup with a press sleeve; the 2130 g ring mass makes cocking during fitting a direct raceway-brinelling risk.
- The standard-section 30200 family at 85 mm bore (150×30.5 mm assembled) carries more capacity than the lighter 320/329 sections but generates more preload heat; confirm oil availability before running near the 3,200 r/min oil ceiling.
- On slash-size and T-code bearings confirm the full code on both cone and cup before fitting: the 85 mm bore alone does not identify the cup, and a mismatched cone/cup set has no catalogue rating.
- Replacing one half of an adjusted pair without resetting end play negates the 30.5 mm T dimension logic: re-adjust the set and re-verify the contact pattern rather than reusing the old spacer stack.
- Never fit the 85 mm cone by hammering the 150 mm cup: force for both press fits goes through the ring faces only, or brinell marks release as noise within the first running hours.
- The 203/232 kN ratings and 27 kN Pu here are NTN Ball and Roller Bearings CAT.No.2203E figures for 30217U (ISO 355 3EB); 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 30217U?
30217U is a metric 4T tapered roller bearing to ISO 355: 85 mm bore, 150 mm outside diameter and 30.5 mm assembled width T (3.346 × 5.906 × 1.201 in). From NTN Ball and Roller Bearings CAT.No.2203E: C 203 kN, C0 232 kN, Pu 27 kN, grease limiting speed 2,400 r/min, oil speed 3,200 r/min, mass about 2130 g. It is an open, separable cone/cup bearing with a pressed-steel cage.
What does the 4T prefix mean on 30217U?
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 (30217U); the lower-case 4t- factory spelling of the code is retained among the search aliases.
How does the 30217U designation encode the 85 mm bore and what is 3EB?
last two digits 17 are the ISO bore code, ×5 = 85 mm (codes 00–03 use the 10/12/15/17 exception table). The 150 mm OD and 30.5 mm assembled T follow the ISO 355 dimension-series plan. 3EB 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 30217U 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 30217U 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 30217U mean?
Suffix reading on 30217U: 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.