30317DU bearing: complete specifications & equivalents
The 30317DU 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 | 274 kN |
| Basic static load rating C0 | 293 kN |
| Fatigue load limit Pu | 33 kN |
| Limiting speed (mechanical) | 1900 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 4740 g |
| Manufacturer designation | NTN 30317DU |
| 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 |
|---|---|---|---|
| 30317DU | 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 30317DU model number is decoded
30317DU belongs to the NTN metric 4T tapered roller range (large-OD 30300 family with the steeper contact angle); the open bearing leaves sealing to the application and is normally ordered and mounted as an adjustable matched pair. On the NTN nameplate the parts carry 4T plus the bare code, while 2203E orders 30317DU by the metric ISO 355 number (ISO series abbreviation 7GB): 85 mm bore, 180 mm OD. Suffix reading on 30317DU: U marks the reinforced/uprated internal design of the bare number, a separate order number with higher load capacity than the basic execution; the CA/CU/DU letter marks a contact-angle/internal-geometry variant of the same envelope — quote the exact suffix because axial/radial capacity split differs; the suffix is part of the order number and the variants are not interchangeable articles. 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. With a rotating shaft a k5/m5 shaft seat and a press-fit cup are typical catalogue practice for 30317DU; reverse the logic if the cup rotates, and re-verify against load direction and magnitude.
Typical equipment & failure modes
Common applications
- rolling-mill auxiliary and pinion-stand shafts
- large conveyor and bucket-elevator pulleys
- mineral-processing feeder and crusher auxiliaries
- marine winch and deck-machinery shafts
Known failure patterns
- cup creep and housing fretting when the specified outer-ring press fit is not achieved
- 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
- 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 4740 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 1,900 r/min grease limit and the thrust load split.
- The 47.5 mm section leaves little room for an oversized shaft fillet; check the mounting-chamfer table for 30317DU or the ring will bottom out on the radius instead of the shoulder face.
- Replacing one half of an adjusted pair without resetting end play negates the 44.5 mm T dimension logic: re-adjust the set and re-verify the contact pattern rather than reusing the old spacer stack.
- ISO 355 makes the 85×180 mm envelope interchangeable but not the ratings: NTN prints 274/293 kN for this execution, and a cheaper same-number part can differ in roller complement and steel.
- The 274/293 kN ratings and 33 kN Pu here are NTN Ball and Roller Bearings CAT.No.2203E figures for 30317DU (ISO 355 7GB); 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 30317DU?
30317DU 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 274 kN, C0 293 kN, Pu 33 kN, grease limiting speed 1,900 r/min, oil speed 2,500 r/min, mass about 4740 g. It is an open, separable cone/cup bearing with a pressed-steel cage.
What does the 4T prefix mean on 30317DU?
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 (30317DU); the lower-case 4t- factory spelling of the code is retained among the search aliases.
How does the 30317DU designation encode the 85 mm bore and what is 7GB?
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. 7GB 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 30317DU list two speeds, 1,900 and 2,500 r/min?
The lower figure, 1,900 r/min, is the grease-lubricated limiting speed — the mechanical ceiling for the cage, rollers and cone-rib contact. With oil lubrication NTN rates 30317DU at 2,500 r/min because oil removes rib-contact heat better. Real limits still depend on preload, oil flow and cooling.
What does the suffix on 30317DU mean?
Suffix reading on 30317DU: U marks the reinforced/uprated internal design of the bare number, a separate order number with higher load capacity than the basic execution; the CA/CU/DU letter marks a contact-angle/internal-geometry variant of the same envelope — quote the exact suffix because axial/radial capacity split differs; 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.