30205-NTN bearing: complete specifications & equivalents
The 30205-NTN is a ISO 355 radial bearing sized 25 x 52 x 16.25 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | NTN |
| Bore diameter d | 25 mm |
| Outer diameter D | 52 mm |
| Width B | 16.25 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | steel |
| Basic dynamic load rating C | 35 kN |
| Basic static load rating C0 | 34 kN |
| Limiting speed (mechanical) | 7300 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 155 g |
| Manufacturer designation | NTN 30205 |
| 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 | 0.984 in |
|---|---|
| Outer diameter D | 2.047 in |
| Width B | 0.64 in |
| ISO bore code | 05 |
| Radial section height (D−d)/2 | 13.5 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) | 4 of 37 |
| Bore above smallest 30200-series size | 10 mm |
Mounting, setting & life for 30205-NTN
Fits & mounting
- Tapered bearings are separable: press the cup square into the housing and fit the cone on the shaft — usually an interference fit on both seats in wheel/hub positions.
- Mount the cone by induction heating (max 120 °C); never strike the cage or rollers directly.
- Shaft and housing shoulders must clear the ring chamfers so the cone and cup seat fully against their faces.
Setting — the step deep-groove bearings never need
- After seating, set the assembly to a defined end play or preload with the locknut/shim arrangement; locknut torque seats the parts — it is not the final adjustment.
- General free-running positions: back the nut off while measuring with a dial indicator to a small end play (commonly around 0.05–0.15 mm for medium metric hubs — follow the OEM value).
- Pinions and stiff arrangements run a controlled preload; too much preload is the classic cause of early spalling and heat.
- Sealed factory-set units exist for specific designations — the open 30205-NTN assumes the application sets and lubricates it.
Lubrication
Open TRBs are lubricated by the application. Fill the bearing with grease (typically around one third to one half of the free cavity — overpacking a TRB causes churning heat) and provide a relubrication path; intervals depend on contamination and temperature, not on catalogue rating alone.
Why the equivalent load matters more here
TRBs carry combined radial and axial loads, so the dynamic equivalent load P is computed with the bearing's e, X and Y factors for the actual thrust ratio — using the radial load alone over-estimates life badly.
Worked L10 life example (illustrative duty)
For roller bearings the life exponent is p = 10/3: L10h = (C/P)10/3 · 106 / (60·n). Taking an example equivalent load P = 7 kN (20% of C) at n = 1,500 r/min — substitute the real P from the X/Y calculation:
C = 35.0 kN → L10h ≈ 2,375 hours
Choosing a series at the same 25 mm bore
| Series | Open execution | OD × width T | C (kN) | C0 (kN) | Limiting speed (r/min) |
|---|---|---|---|---|---|
| 320xx | 32005 | 47 × 15 | 31.5 | 34.0 | 18,900 |
| 302xx | 30205 | 52 × 16.25 | 38.1 | 33.5 | 13,000 |
| 322xx | 32205 | 52 × 19.25 | 47.5 | 45.0 | 17,500 |
| 332xx | 33205 | 52 × 22 | 57.9 | 56.0 | 13,000 |
| 303xx | 30305C | 62 × 18.25 | 46.0 | 41.5 | 6,400 |
| 323xx | 32305 | 62 × 25.25 | 74.1 | 63.0 | 12,000 |
| 313xx | 31305 | 62 × 18.25 | 46.6 | 40.0 | 11,000 |
Different series at the same bore are not drop-in swaps — OD, width and contact angle all change — and a cone number alone never identifies a complete set. Verify matches per the cross-reference levels guide; envelope variants are on the 25×52×16.25 envelope page.
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| 30205 | 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 30205-NTN model number is decoded
30205 is the NTN 4T catalogue entry for a 25×52×16.25 mm metric tapered roller bearing — separable cone and cup, designed for combined radial and axial load as an individually adjusted bearing. Reading the designation: the leading five digits follow the ISO 355 metric plan (dimension family plus two-digit bore code), and 30205 resolves to 25 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. The 13.5 mm radial section carries the roller complement across the 25–52 mm envelope; section and contact angle differ between NTN metric families even at the same bore, so 302/322/323 are not drop-in swaps. The 13.5 mm section height over the 25 mm bore positions the load centre; axial location of the pair depends on that contact line, so spacer faces must be square within the P0 tolerance of the bearing. Mount the 25 mm-bore cone on the shaft first (induction heat, max 120 °C), fit the cup square in its housing, then set preload or end play; never drive the cup home through the rollers of 30205.
Typical equipment & failure modes
Common applications
- light-vehicle differential and pinion shafts
- agricultural implement hubs and ground-tool drives
- small gearbox input shafts with combined load
- scooter and light-powersport wheel and gear positions
Known failure patterns
- cup creep and housing fretting when the specified outer-ring press fit is not achieved
- 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 fatigue when the pair is run continuously near the grease limiting speed without oil cooling
- rolling-contact fatigue after the catalogue L10 life at the actual combined load
Selection pitfalls — read before you substitute
- At 25 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 30205 pair with a dial indicator rather than by feel.
- The standard-section 30200 family at 25 mm bore (52×16.25 mm assembled) carries more capacity than the lighter 320/329 sections but generates more preload heat; confirm oil availability before running near the 9,800 r/min oil ceiling.
- The 13.5 mm section leaves little room for an oversized shaft fillet; check the mounting-chamfer table for 30205 or the ring will bottom out on the radius instead of the shoulder face.
- On slash-size and T-code bearings confirm the full code on both cone and cup before fitting: the 25 mm bore alone does not identify the cup, and a mismatched cone/cup set has no catalogue rating.
- The U/UTG/X/C/CA/D suffix variants of a base number share the bore but not the article: ordering 30205 by size alone can deliver the wrong contact-angle execution for a pinion position.
- The 35/34 kN ratings here are NTN Ball and Roller Bearings CAT.No.2203E figures for 30205 (ISO 355 3CC); 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 30205?
30205 is a metric 4T tapered roller bearing to ISO 355: 25 mm bore, 52 mm outside diameter and 16.25 mm assembled width T (0.984 × 2.047 × 0.64 in). From NTN Ball and Roller Bearings CAT.No.2203E: C 35 kN, C0 34 kN (2203E prints no Pu for this size), grease limiting speed 7,300 r/min, oil speed 9,800 r/min, mass about 155 g. It is an open, separable cone/cup bearing with a pressed-steel cage.
What does the 4T prefix mean on 30205?
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 (30205); the lower-case 4t- factory spelling of the code is retained among the search aliases.
How does the 30205 designation encode the 25 mm bore and what is 3CC?
last two digits 05 are the ISO bore code, ×5 = 25 mm (codes 00–03 use the 10/12/15/17 exception table). The 52 mm OD and 16.25 mm assembled T follow the ISO 355 dimension-series plan. 3CC 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 30205 list two speeds, 7,300 and 9,800 r/min?
The lower figure, 7,300 r/min, is the grease-lubricated limiting speed — the mechanical ceiling for the cage, rollers and cone-rib contact. With oil lubrication NTN rates 30205 at 9,800 r/min because oil removes rib-contact heat better. Real limits still depend on preload, oil flow and cooling.
What does the suffix on 30205 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.