30316U bearing: complete specifications & equivalents
The 30316U is a ISO 355 radial bearing sized 80 x 170 x 42.5 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | NTN |
| Bore diameter d | 80 mm |
| Outer diameter D | 170 mm |
| Width B | 42.5 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | steel |
| Basic dynamic load rating C | 325 kN |
| Basic static load rating C0 | 350 kN |
| Fatigue load limit Pu | 39.5 kN |
| Limiting speed (mechanical) | 2300 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 4410 g |
| Manufacturer designation | NTN 30316U |
| 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 | 3.15 in |
|---|---|
| Outer diameter D | 6.693 in |
| Width B | 1.673 in |
| ISO bore code | — |
| Radial section height (D−d)/2 | 45 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) | 15 of 32 |
| Bore above smallest 30300-series size | 65 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| 30316U | 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 30316U model number is decoded
In NTN Ball and Roller Bearings CAT.No.2203E, the NTN order number 30316U denotes the large-OD 30300 family with the steeper contact angle of metric tapered roller bearings, 80 mm bore, 170 mm outside diameter and 42.5 mm assembled width T (3.15 × 6.693 × 1.673 in) to the ISO 355 boundary plan. On the NTN nameplate the parts carry 4T plus the bare code, while 2203E orders 30316U by the metric ISO 355 number (ISO series abbreviation 2GB): 80 mm bore, 170 mm OD. The rollers run with their large ends against the cone's integral guide rib; the rib/end-flange contact carries the thrust component and is the reason lubricant must reach the rib face of 30316U, not only the raceway. Catalogue mass of the 30316U set is 4410 g (0.174 lb cone + cup); abutment and shaft shoulder design must carry that mass square to the axis. Fillet radii must clear the ring chamfers of the 170 mm cup and 80 mm cone; use undercut shoulders so the rings seat fully rather than bridging on a shaft radius.
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
- smearing on the roller large ends and cone rib after a dry start with preload but no oil film
- flaking on one cone only when a back-to-back / face-to-face pair is loaded unevenly by a bent shaft
- cage fatigue when the pair is run continuously near the grease limiting speed without oil cooling
- edge loading when shaft deflection exceeds the few arc-minutes of misalignment the adjusted pair allows
Selection pitfalls — read before you substitute
- Mount the 80 mm cone by induction heating (max 120 °C) and the cup with a press sleeve; the 4410 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 80 mm bore; do not swap to the lighter family without re-checking the 2,300 r/min grease limit and the thrust load split.
- ISO 355 makes the 80×170 mm envelope interchangeable but not the ratings: NTN prints 325/350 kN for this execution, and a cheaper same-number part can differ in roller complement and steel.
- On slash-size and T-code bearings confirm the full code on both cone and cup before fitting: the 80 mm bore alone does not identify the cup, and a mismatched cone/cup set has no catalogue rating.
- Back-to-back and face-to-face arrangements react differently to shaft bending: pick the pair orientation for the moment load before locking the 80 mm shoulder geometry, because retrofitting flips the cups.
- The 325/350 kN ratings and 39.5 kN Pu here are NTN Ball and Roller Bearings CAT.No.2203E figures for 30316U (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 30316U?
30316U is a metric 4T tapered roller bearing to ISO 355: 80 mm bore, 170 mm outside diameter and 42.5 mm assembled width T (3.15 × 6.693 × 1.673 in). From NTN Ball and Roller Bearings CAT.No.2203E: C 325 kN, C0 350 kN, Pu 39.5 kN, grease limiting speed 2,300 r/min, oil speed 3,000 r/min, mass about 4410 g. It is an open, separable cone/cup bearing with a pressed-steel cage.
What does the 4T prefix mean on 30316U?
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 (30316U); the lower-case 4t- factory spelling of the code is retained among the search aliases.
How does the 30316U designation encode the 80 mm bore and what is 2GB?
last two digits 16 are the ISO bore code, ×5 = 80 mm (codes 00–03 use the 10/12/15/17 exception table). The 170 mm OD and 42.5 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 30316U list two speeds, 2,300 and 3,000 r/min?
The lower figure, 2,300 r/min, is the grease-lubricated limiting speed — the mechanical ceiling for the cage, rollers and cone-rib contact. With oil lubrication NTN rates 30316U 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 30316U mean?
Suffix reading on 30316U: 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.