30209-NTN bearing: complete specifications & equivalents
The 30209-NTN is a ISO 355 radial bearing sized 45 x 85 x 20.75 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | NTN |
| Bore diameter d | 45 mm |
| Outer diameter D | 85 mm |
| Width B | 20.75 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | steel |
| Basic dynamic load rating C | 75 kN |
| Basic static load rating C0 | 78.5 kN |
| Limiting speed (mechanical) | 4400 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 493 g |
| Manufacturer designation | NTN 30209 |
| 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 & 30200-series range
| Bore d | 1.772 in |
|---|---|
| Outer diameter D | 3.346 in |
| Width B | 0.817 in |
| ISO bore code | 09 |
| Radial section height (D−d)/2 | 20 mm |
| Smallest bore in 30200-series | 15 mm |
| Largest outer diameter in 30200-series | 580 mm |
| Width range across 30200-series | 11.75–104 mm |
| Bore position in 30200-series (smallest first) | 9 of 37 |
| Bore above smallest 30200-series size | 30 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| 30209 | 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 30209-NTN model number is decoded
For a 45 mm shaft with a thrust component, NTN lists 30209, a metric 4T tapered roller bearing of 75 kN C and 78.5 kN C0 inside the 85 mm OD, 20.75 mm-wide assembled set. Reading the designation: the leading five digits follow the ISO 355 metric plan (dimension family plus two-digit bore code), and 30209 resolves to 45 mm bore; the NTN factory mark 4T is stamped on cone and cup but is a brand mark, not a size code, so the catalogue sku is printed without it. Individually mounted, 30209 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. 2203E does not print a Pu fatigue load limit for 30209; life work for this size uses the 75/78.5 kN C/C0 pair directly. After mounting check the contact pattern with marking blue: a pattern biased to the large or small roller end means the 45 mm pair is misadjusted and the 20.75 mm T set will edge-load in service.
Typical equipment & failure modes
Common applications
- pump and compressor drive shafts carrying combined load
- machine-tool gearbox and headstock shafts
- axle final-drive and differential positions
- construction-equipment wheel and pivot hubs
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 fatigue when the pair is run continuously near the grease limiting speed without oil cooling
- water-induced pitting when the open bearing is exposed to washdown without external seals
Selection pitfalls — read before you substitute
- Hub and pinion bearings of this 45 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 30209.
- The standard-section 30200 family at 45 mm bore (85×20.75 mm assembled) carries more capacity than the lighter 320/329 sections but generates more preload heat; confirm oil availability before running near the 5,900 r/min oil ceiling.
- The U/UTG/X/C/CA/D suffix variants of a base number share the bore but not the article: ordering 30209 by size alone can deliver the wrong contact-angle execution for a pinion position.
- The U/UTG/X/C/CA/D suffix variants of a base number share the bore but not the article: ordering 30209 by size alone can deliver the wrong contact-angle execution for a pinion position.
- Never fit the 45 mm cone by hammering the 85 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 75/78.5 kN ratings here are NTN Ball and Roller Bearings CAT.No.2203E figures for 30209 (ISO 355 3DB); 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 30209?
30209 is a metric 4T tapered roller bearing to ISO 355: 45 mm bore, 85 mm outside diameter and 20.75 mm assembled width T (1.772 × 3.346 × 0.817 in). From NTN Ball and Roller Bearings CAT.No.2203E: C 75 kN, C0 78.5 kN (2203E prints no Pu for this size), grease limiting speed 4,400 r/min, oil speed 5,900 r/min, mass about 493 g. It is an open, separable cone/cup bearing with a pressed-steel cage.
What does the 4T prefix mean on 30209?
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 (30209); the lower-case 4t- factory spelling of the code is retained among the search aliases.
How does the 30209 designation encode the 45 mm bore and what is 3DB?
last two digits 09 are the ISO bore code, ×5 = 45 mm (codes 00–03 use the 10/12/15/17 exception table). The 85 mm OD and 20.75 mm assembled T follow the ISO 355 dimension-series plan. 3DB 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 30209 list two speeds, 4,400 and 5,900 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 30209 at 5,900 r/min because oil removes rib-contact heat better. Real limits still depend on preload, oil flow and cooling.
What does the suffix on 30209 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.