30205 bearing: complete specifications & equivalents
The 30205 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 | SKF |
| 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, stamped ribbon (J-type) |
| Basic dynamic load rating C | 38.1 kN |
| Basic static load rating C0 | 33.5 kN |
| Fatigue load limit Pu | 3.45 kN |
| Reference speed (thermal) | 11000 rpm |
| Limiting speed (mechanical) | 13000 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 150 g |
| Manufacturer designation | SKF 30205 |
| Standard | ISO 355 |
| Catalog version | SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 8.1 metric single-row TRB |
| Last verified | 2026-09-26 |
Source: catalog reference (SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 8.1 metric single-row TRB) · extracted 2026-09-26
Parameters extracted from the official SKF Rolling Bearings catalogue (SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 8.1 metric single-row TRB); SKF® and SKF Explorer® are trademarks of AB SKF, used here for identification only — mpnbase is not an authorized SKF distributor. Boundary dimensions are ISO 15 interchangeable; current production values may differ, verify at skf.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
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 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 = 7.6 kN (20% of C) at n = 1,500 r/min — substitute the real P from the X/Y calculation:
C = 38.1 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 | ISO 15 | full Dimensions and internal design equivalent — standard interchange. | ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier. |
| 30205-NTN | NTN | 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 model number is decoded
SKF 30205 (SKF 30205) is the standard section tapered roller choice for a 25 mm shaft — one row of tapered rollers on an asymmetric raceway inside the 52×16.25 mm ISO 355 envelope.Digit by digit, 30205 reads as bearing type 3 (single-row tapered roller), standard section series 0, and bore reference 05 resolving to 25 mm; 52 mm OD and 16.25 mm width are the matching ISO 355 boundary values. SKF lists the plain number as the basic execution; letter suffixes such as B denote a steeper contact angle and are different order numbers. The 13.5 mm radial section height ((52−25)/2) and 150 g catalogue mass frame a 25 mm bore bearing rated at 38.1 kN C — roughly 1.52 kN of dynamic capacity per millimetre of bore before application factors. Fit selection follows the rotating ring — interference on a rotating cone — and two 30205 units are required to take reversing thrust; keep the induced axial load inside the rated capacity when calculating the pair.
Typical equipment & failure modes
Common applications
- electric-motor pinion shafts
- steering knuckles and small differentials
- agricultural implement hubs
- small conveyor drive pulleys
Known failure patterns
- cup or cone misalignment when the separable rings are not seated square during mounting
- loose cup rotation in the housing when the specified press fit is not achieved
- preload loss as the mounted pair relaxes, letting rollers skid and smear the raceways
- axial overload spalling at the roller-rib contact beyond the single-row thrust rating
- cage pocket scoring when the bearing starts cold with grease of too-high base-oil viscosity
- edge loading from shaft deflection or housing misalignment
Selection pitfalls — read before you substitute
- At a 25 mm bore the thin cone and cup are easily distorted by an over-tight shaft nut; check seat runout (target Ra ≤ 0.8 µm) and torque the locknut progressively — a pinched 30205 shows up as gearbox vibration long before it fails.
- The 302 series at 25 mm bore (52×16.25 mm) is the standard tapered-roller envelope; stepping to a 32205 or 32305 changes OD, width and heat generation — it is not a drop-in swap when the housing and speed are fixed.
- O (back-to-back) pairs are stiffer against moments, X (face-to-face) pairs tolerate misalignment and thermal growth better; choosing the arrangement from the 2D drawing rather than the actual shaft thermal expansion is a common 30205 mounting error.
- At the 38.1 kN rating of 30205, preload class changes stiffness by tens of percent but also heat generation; select light preload for the 13,000 r/min speed end and heavier preload only where moment stiffness dominates.
- Catalogue reference speed and limiting speed are different limits: the 11,000 r/min reference is a thermal criterion under load, while the 13,000 r/min limiting value is the mechanical ceiling — observe both.
- The 38.1/33.5 kN ratings are SKF catalogue 17000 values for the basic execution; SKF can revise internal geometry without changing the order number, so keep the catalogue version (PUB BU/P1 17000/1 EN, 2018) with the specification and re-verify for critical drives.
- SKF lists several executions of 30205 (basic, B steeper angle, Q/J2 clearance variants); they are not interchangeable order numbers — quote the full SKF 30205 designation when purchasing and match the execution to the mounting arrangement.
Frequently asked questions
What are the dimensions and catalogue data of 30205?
The SKF 30205 is a single-row tapered roller bearing with 25 mm bore, 52 mm outer diameter and 16.25 mm width (0.984 × 2.047 × 0.64 in) per ISO 355. From SKF catalogue PUB BU/P1 17000: basic dynamic load rating C 38.1 kN, C0 33.5 kN, fatigue load limit Pu 3.45 kN, reference speed 11,000 r/min, limiting speed 13,000 r/min, mass about 150 g. It is an open, separable bearing with a pressed-steel cage.
How does the 30205 bore code work?
The last two digits of 30205 are bore code 05, so 05 × 5 = 25 mm bore. The 52 mm OD and 16.25 mm width come from the ISO 355 dimension-series plan, shared with other tapered bearings of the same code.
What do the 30205 series and basic execution designations mean?
The leading 3 marks a single-row tapered roller bearing; the second digit 0 is the ISO 355 series (standard section). The SKF catalogue lists the ISO 355 dimension-series code after the bare number. A steeper-contact-angle variant (B suffix) is a different order number and is not interchangeable with the basic execution.
Can a single 30205 take axial load in both directions?
No — one single-row tapered roller bearing reacts thrust in one direction only, and under radial load its contact angle induces an axial force. Use two bearings as a matched pair: O (back-to-back) for a rigid, moment-resisting arrangement, X (face-to-face) where thermal expansion must be tolerated, or tandem where one-direction thrust is shared.
How does 30205 compare with a ball bearing of the same bore?
A tapered roller bearing has line contact and a steep contact angle: much higher combined axial-plus-radial capacity and shock resistance than a ball bearing of the same bore, at the cost of speed, one-direction thrust, mandatory pairing for reversing loads and a minimum axial load requirement. A ball bearing cannot be dropped into a combined-load 30205 position and vice versa — verify load direction, Fa/Fr ratio and speed before substituting.
Reviewed & verified by the MPN Base engineering desk against source catalog SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 8.1 metric single-row TRB on 2026-09-26. Read our editorial & correction policy.