30317U bearing: complete specifications & equivalents
The 30317U is a ISO 355 radial bearing sized 85 x 180 x 44.5 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 | 180 mm |
| Width B | 44.5 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | steel |
| Basic dynamic load rating C | 335 kN |
| Basic static load rating C0 | 365 kN |
| Fatigue load limit Pu | 40.5 kN |
| Limiting speed (mechanical) | 2100 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 5010 g |
| Manufacturer designation | NTN 30317U |
| 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 & 30300-series range
| Bore d | 3.346 in |
|---|---|
| Outer diameter D | 7.087 in |
| Width B | 1.752 in |
| ISO bore code | — |
| Radial section height (D−d)/2 | 47.5 mm |
| Smallest bore in 30300-series | 15 mm |
| Largest outer diameter in 30300-series | 500 mm |
| Width range across 30300-series | 14.25–105 mm |
| Bore position in 30300-series (smallest first) | 16 of 32 |
| Bore above smallest 30300-series size | 70 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| 30317U | ISO 15 | full Dimensions and internal design equivalent — standard interchange. | ISO 15 boundary-dimension envelope; brand-specific OEM equivalents (NSK/FAG/NTN) pending multi-source data. |
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 30317U model number is decoded
The NTN 2203E table prints 30317U in the large-OD 30300 family with the steeper contact angle: 85 mm bore, 180 mm cup OD, 44.5 mm T, with a grease limiting speed of 2,100 r/min and an oil-lubricated ceiling of 2,900 r/min. NTN also quotes this bearing with its ISO 355 dimension-series abbreviation, 2GB, which is the maker-neutral cross-reference for the 85×180 mm envelope; 4T is NTN's own tapered-roller brand mark on the parts. 2203E lists two speed ceilings for 30317U: 2,100 r/min with grease lubrication (the limiting speed) and 2,900 r/min with oil, the higher oil value reflecting better heat removal from the cone rib. The 47.5 mm section height over the 85 mm bore positions the load centre; axial location of the pair depends on that contact line, so spacer faces must be square within the P0 tolerance of the bearing. Re-adjustment after bedding-in is standard practice: re-check end play once the paired 30317U 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
- cone-raceway spalling at the large rib when preload is set too high for the lubricant film
- 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
- indentation of the raceways by hard particles in unsealed open arrangements
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 5010 g ring mass makes cocking during fitting a direct raceway-brinelling risk.
- The steeper contact angle of the large-OD 30300 family with the steeper contact angle raises axial capacity but lowers the speed ceiling against a 302/322 bearing at 85 mm bore; do not swap to the lighter family without re-checking the 2,100 r/min grease limit and the thrust load split.
- Never fit the 85 mm cone by hammering the 180 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 U/UTG/X/C/CA/D suffix variants of a base number share the bore but not the article: ordering 30317U by size alone can deliver the wrong contact-angle execution for a pinion position.
- Grease packs must leave free volume in the 44.5 mm-wide set; over-greasing a paired bearing churning at the 2,900 r/min oil-band speed raises temperature and destroys the preload setting.
- The 335/365 kN ratings and 40.5 kN Pu here are NTN Ball and Roller Bearings CAT.No.2203E figures for 30317U (ISO 355 2GB); 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 30317U?
30317U is a metric 4T tapered roller bearing to ISO 355: 85 mm bore, 180 mm outside diameter and 44.5 mm assembled width T (3.346 × 7.087 × 1.752 in). From NTN Ball and Roller Bearings CAT.No.2203E: C 335 kN, C0 365 kN, Pu 40.5 kN, grease limiting speed 2,100 r/min, oil speed 2,900 r/min, mass about 5010 g. It is an open, separable cone/cup bearing with a pressed-steel cage.
What does the 4T prefix mean on 30317U?
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 (30317U); the lower-case 4t- factory spelling of the code is retained among the search aliases.
How does the 30317U designation encode the 85 mm bore and what is 2GB?
last two digits 17 are the ISO bore code, ×5 = 85 mm (codes 00–03 use the 10/12/15/17 exception table). The 180 mm OD and 44.5 mm assembled T follow the ISO 355 dimension-series plan. 2GB 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 30317U list two speeds, 2,100 and 2,900 r/min?
The lower figure, 2,100 r/min, is the grease-lubricated limiting speed — the mechanical ceiling for the cage, rollers and cone-rib contact. With oil lubrication NTN rates 30317U at 2,900 r/min because oil removes rib-contact heat better. Real limits still depend on preload, oil flow and cooling.
What does the suffix on 30317U mean?
Suffix reading on 30317U: 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.