30315DU bearing: complete specifications & equivalents
The 30315DU is a ISO 355 radial bearing sized 75 x 160 x 40 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | NTN |
| Bore diameter d | 75 mm |
| Outer diameter D | 160 mm |
| Width B | 40 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | steel |
| Basic dynamic load rating C | 238 kN |
| Basic static load rating C0 | 256 kN |
| Fatigue load limit Pu | 29.8 kN |
| Limiting speed (mechanical) | 2100 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 3460 g |
| Manufacturer designation | NTN 30315DU |
| 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 | 2.953 in |
|---|---|
| Outer diameter D | 6.299 in |
| Width B | 1.575 in |
| ISO bore code | — |
| Radial section height (D−d)/2 | 42.5 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) | 14 of 32 |
| Bore above smallest 30300-series size | 60 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| 30315DU | 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 30315DU model number is decoded
30315DU is a metric single-row tapered roller bearing in the NTN 4T programme: a pressed-steel cage guides profiled rollers between a separable cone and cup on the 75×160 mm ISO 355 envelope, with 40 mm overall assembled width T. NTN also quotes this bearing with its ISO 355 dimension-series abbreviation, 7GB, which is the maker-neutral cross-reference for the 75×160 mm envelope; 4T is NTN's own tapered-roller brand mark on the parts. NTN grades 4T metric bearings as open bearings without integral seals; at 75 mm bore the application supplies the seals and the grease fill or oil supply to the 7GB ISO 355 assembly. The 3.2 kN-per-mm-bore capacity figure for 30315DU summarises the 238 kN rating over 75 mm bore; use it to sanity-check an interchange candidate before swapping brands. Open 4T bearings need application seals; without them the grease at the cone rib of 30315DU washes out and the rib/roller-end contact smears on the first wet or dusty shift.
Typical equipment & failure modes
Common applications
- marine winch and deck-machinery shafts
- paper-machine press-section rolls
- large agricultural and forestry machine axles
- heavy industrial gearboxes and crane travel drives
Known failure patterns
- cup creep and housing fretting when the specified outer-ring press fit is not achieved
- preload loss from racewear when one bearing of the paired set is replaced without re-adjusting end play
- rib scoring when axial load is carried beyond the cone rib capacity of the adjusted pair
- pressed-steel cage pocket wear from roller skid at light radial load and high speed
- water-induced pitting when the open bearing is exposed to washdown without external seals
Selection pitfalls — read before you substitute
- Mount the 75 mm cone by induction heating (max 120 °C) and the cup with a press sleeve; the 3460 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 75 mm bore; do not swap to the lighter family without re-checking the 2,100 r/min grease limit and the thrust load split.
- Grease packs must leave free volume in the 40 mm-wide set; over-greasing a paired bearing churning at the 2,800 r/min oil-band speed raises temperature and destroys the preload setting.
- The U/UTG/X/C/CA/D suffix variants of a base number share the bore but not the article: ordering 30315DU by size alone can deliver the wrong contact-angle execution for a pinion position.
- The 42.5 mm section leaves little room for an oversized shaft fillet; check the mounting-chamfer table for 30315DU or the ring will bottom out on the radius instead of the shoulder face.
- The 238/256 kN ratings and 29.8 kN Pu here are NTN Ball and Roller Bearings CAT.No.2203E figures for 30315DU (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 30315DU?
30315DU is a metric 4T tapered roller bearing to ISO 355: 75 mm bore, 160 mm outside diameter and 40 mm assembled width T (2.953 × 6.299 × 1.575 in). From NTN Ball and Roller Bearings CAT.No.2203E: C 238 kN, C0 256 kN, Pu 29.8 kN, grease limiting speed 2,100 r/min, oil speed 2,800 r/min, mass about 3460 g. It is an open, separable cone/cup bearing with a pressed-steel cage.
What does the 4T prefix mean on 30315DU?
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 (30315DU); the lower-case 4t- factory spelling of the code is retained among the search aliases.
How does the 30315DU designation encode the 75 mm bore and what is 7GB?
last two digits 15 are the ISO bore code, ×5 = 75 mm (codes 00–03 use the 10/12/15/17 exception table). The 160 mm OD and 40 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 30315DU list two speeds, 2,100 and 2,800 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 30315DU at 2,800 r/min because oil removes rib-contact heat better. Real limits still depend on preload, oil flow and cooling.
What does the suffix on 30315DU mean?
Suffix reading on 30315DU: 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.