30302-NTN bearing: complete specifications & equivalents
The 30302-NTN is a ISO 355 radial bearing sized 15 x 42 x 14.25 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | NTN |
| Bore diameter d | 15 mm |
| Outer diameter D | 42 mm |
| Width B | 14.25 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | steel |
| Basic dynamic load rating C | 25.8 kN |
| Basic static load rating C0 | 20.8 kN |
| Limiting speed (mechanical) | 9900 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 96 g |
| Manufacturer designation | NTN 30302 |
| 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 | 0.591 in |
|---|---|
| Outer diameter D | 1.654 in |
| Width B | 0.561 in |
| ISO bore code | 02 |
| Radial section height (D−d)/2 | 13.5 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) | 1 of 32 |
| Bore above smallest 30300-series size | 0 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| 30302 | SKF | full Dimensions and internal design equivalent — standard interchange. | Identical ISO 15 envelope, seal and ratings band — standard interchange; re-verify precision class and clearance per supplier. |
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 30302-NTN model number is decoded
30302 is the NTN 4T catalogue entry for a 15×42×14.25 mm metric tapered roller bearing — separable cone and cup, designed for combined radial and axial load as an individually adjusted bearing. NTN also quotes this bearing with its ISO 355 dimension-series abbreviation, 2FB, which is the maker-neutral cross-reference for the 15×42 mm envelope; 4T is NTN's own tapered-roller brand mark on the parts. Individually mounted, 30302 takes axial force in one direction only; two bearings are arranged face-to-face (X) or back-to-back (O) according to the moment stiffness and misalignment the shaft requires. Selection: C 25.8 kN against C0 20.8 kN gives a C0/C ratio of 0.81 for the 15 mm bore, and the equivalent combined load must keep below the rating at the target L10 with the pair counted as one unit. Fillet radii must clear the ring chamfers of the 42 mm cup and 15 mm cone; use undercut shoulders so the rings seat fully rather than bridging on a shaft radius.
Typical equipment & failure modes
Common applications
- agricultural implement hubs and ground-tool drives
- small gearbox input shafts with combined load
- scooter and light-powersport wheel and gear positions
- small conveyor pulley 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
- false brinelling on a stationary paired set exposed to external vibration
Selection pitfalls — read before you substitute
- At 15 mm bore the thin section and small rollers are adjustment-sensitive: a quarter-turn of the locknut moves end play by more than on large bearings, so set the 30302 pair with a dial indicator rather than by feel.
- 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 15 mm bore; do not swap to the lighter family without re-checking the 9,900 r/min grease limit and the thrust load split.
- Grease packs must leave free volume in the 14.25 mm-wide set; over-greasing a paired bearing churning at the 13,000 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 30302 by size alone can deliver the wrong contact-angle execution for a pinion position.
- Never fit the 15 mm cone by hammering the 42 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 25.8/20.8 kN ratings here are NTN Ball and Roller Bearings CAT.No.2203E figures for 30302 (ISO 355 2FB); 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 30302?
30302 is a metric 4T tapered roller bearing to ISO 355: 15 mm bore, 42 mm outside diameter and 14.25 mm assembled width T (0.591 × 1.654 × 0.561 in). From NTN Ball and Roller Bearings CAT.No.2203E: C 25.8 kN, C0 20.8 kN (2203E prints no Pu for this size), grease limiting speed 9,900 r/min, oil speed 13,000 r/min, mass about 96 g. It is an open, separable cone/cup bearing with a pressed-steel cage.
What does the 4T prefix mean on 30302?
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 (30302); the lower-case 4t- factory spelling of the code is retained among the search aliases.
How does the 30302 designation encode the 15 mm bore and what is 2FB?
last two digits 02 are the ISO bore code, ×5 = 15 mm (codes 00–03 use the 10/12/15/17 exception table). The 42 mm OD and 14.25 mm assembled T follow the ISO 355 dimension-series plan. 2FB 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 30302 list two speeds, 9,900 and 13,000 r/min?
The lower figure, 9,900 r/min, is the grease-lubricated limiting speed — the mechanical ceiling for the cage, rollers and cone-rib contact. With oil lubrication NTN rates 30302 at 13,000 r/min because oil removes rib-contact heat better. Real limits still depend on preload, oil flow and cooling.
What does the suffix on 30302 mean?
It is the basic open 4T execution — steel cage, adjusted mounting, no seal or feature suffix. NTN uses U for the uprated design, UTG for ULTAGE large-bearing specs, X for the ISO boundary section, and C/CA/D/A for contact-angle or internal-design variants; all are separate order numbers.
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.