30307D bearing: complete specifications & equivalents
The 30307D is a ISO 355 radial bearing sized 35 x 80 x 22.75 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | NTN |
| Bore diameter d | 35 mm |
| Outer diameter D | 80 mm |
| Width B | 22.75 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | steel |
| Basic dynamic load rating C | 70.5 kN |
| Basic static load rating C0 | 70 kN |
| Limiting speed (mechanical) | 4400 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 527 g |
| Manufacturer designation | NTN 30307D |
| 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 | 1.378 in |
|---|---|
| Outer diameter D | 3.15 in |
| Width B | 0.896 in |
| ISO bore code | — |
| Radial section height (D−d)/2 | 22.5 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) | 6 of 32 |
| Bore above smallest 30300-series size | 20 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| 30307D | 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 30307D model number is decoded
The NTN 2203E table prints 30307D in the large-OD 30300 family with the steeper contact angle: 35 mm bore, 80 mm cup OD, 22.75 mm T, with a grease limiting speed of 4,400 r/min and an oil-lubricated ceiling of 5,800 r/min. The last two digits 07 are the ISO bore code, ×5 = 35 mm (codes 00–03 use the 10/12/15/17 exception table) under the ISO 355 numbering; the 22.75 mm value printed here is T, the width of the fully assembled cone-plus-cup set, not the inner-ring width alone. The printed contact-angle geometry gives the large-OD 30300 family with the steeper contact angle its characteristic load split — at 70.5/70 kN (C/C0) the static rating is about 0.99× C, typical of tapered bearings proportioned for heavy combined duty. Imperial cross-check for the drawing: 35×80×22.75 mm is 1.378 × 3.15 × 0.896 in; ISO 355 makes the envelope interchangeable but C/C0, 70.5/70 kN, is NTN-specific. With a rotating shaft a k5/m5 shaft seat and a press-fit cup are typical catalogue practice for 30307D; reverse the logic if the cup rotates, and re-verify against load direction and magnitude.
Typical equipment & failure modes
Common applications
- truck and bus wheel hubs in paired arrangements
- industrial gearbox and speed-reducer shafts
- bevel and helical pinion drives with high thrust component
- pump and compressor drive shafts carrying combined load
Known failure patterns
- cone-raceway spalling at the large rib when preload is set too high for the lubricant film
- 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
- cage damage from a mounting blow delivered through the roller complement instead of the ring face
- rolling-contact fatigue after the catalogue L10 life at the actual combined load
Selection pitfalls — read before you substitute
- Hub and pinion bearings of this 35 mm bore class are commonly adjusted in pairs; verify end play against the axle drawing and re-torque after bedding-in rather than trusting the initial preload on 30307D.
- 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 35 mm bore; do not swap to the lighter family without re-checking the 4,400 r/min grease limit and the thrust load split.
- Never fit the 35 mm cone by hammering the 80 mm cup: force for both press fits goes through the ring faces only, or brinell marks release as noise within the first running hours.
- Open 30307D units have no seals: a wheel-hub or gearbox application needs external sealing or the 4,400 r/min grease figure is meaningless once water reaches the cone rib.
- Minimum load matters at high speed: an unloaded 30307D at a large fraction of 4,400 r/min lets rollers skid and smear the cone rib; spring-preload lightly loaded pair arrangements.
- The 70.5/70 kN ratings here are NTN Ball and Roller Bearings CAT.No.2203E figures for 30307D (ISO 355 7FB); 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 30307D?
30307D is a metric 4T tapered roller bearing to ISO 355: 35 mm bore, 80 mm outside diameter and 22.75 mm assembled width T (1.378 × 3.15 × 0.896 in). From NTN Ball and Roller Bearings CAT.No.2203E: C 70.5 kN, C0 70 kN (2203E prints no Pu for this size), grease limiting speed 4,400 r/min, oil speed 5,800 r/min, mass about 527 g. It is an open, separable cone/cup bearing with a pressed-steel cage.
What does the 4T prefix mean on 30307D?
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 (30307D); the lower-case 4t- factory spelling of the code is retained among the search aliases.
How does the 30307D designation encode the 35 mm bore and what is 7FB?
last two digits 07 are the ISO bore code, ×5 = 35 mm (codes 00–03 use the 10/12/15/17 exception table). The 80 mm OD and 22.75 mm assembled T follow the ISO 355 dimension-series plan. 7FB 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 30307D list two speeds, 4,400 and 5,800 r/min?
The lower figure, 4,400 r/min, is the grease-lubricated limiting speed — the mechanical ceiling for the cage, rollers and cone-rib contact. With oil lubrication NTN rates 30307D at 5,800 r/min because oil removes rib-contact heat better. Real limits still depend on preload, oil flow and cooling.
What does the suffix on 30307D mean?
Suffix reading on 30307D: the trailing A/C/D (or E1) letter marks an NTN contact-angle or internal-design revision of the base number, not a seal or clearance code; 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.