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 |
|---|---|
| Bore diameter d | 25 mm |
| Outer diameter D | 52 mm |
| Width B | 16.25 mm |
| Seal / shield | open |
| Internal clearance | CN available |
| Tolerance class | P0 |
| Cage | steel, stamped ribbon (J-type) |
| Operating temperature | -30 to +120 °C |
| Mass (geometry estimate) | 135 g |
| Standard | ISO 355 |
| Catalog version | iso355-geometry |
| Last verified | 2026-09-24 |
Source: ISO 15 boundary-dimensions standard · extracted 2026-09-24
Standard-interchange bearing: dimensions per ISO 15; CN clearance, P0 tolerance and a stamped-steel cage are catalogue defaults unless the supplier states otherwise, and mass is a geometry-derived estimate. Brand catalogue load ratings and limiting speeds for 30205 are being backfilled — use the inquiry form for certified values.
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 | 20 mm |
| Largest outer diameter in 30200-series | 200 mm |
| Width range across 30200-series | 15.25–41 mm |
| Bore position in 30200-series (smallest first) | 2 of 19 |
| Bore above smallest 30200-series size | 5 mm |
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; 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 30205 model number is decoded
In the 30200-series the last two digits of 30205 encode the bore: code 05 = 25 mm (code × 5 from 04 upward). The ISO 355 envelope is 52 mm outside diameter and 16.25 mm total assembly width T over the separable cone and cup — 0.984 × 2.047 × 0.64 in, with a 13.5 mm radial section height. Tapered rollers carry combined radial and single-direction axial load; bidirectional thrust needs an opposed pair (X face-to-face or O back-to-back) adjusted at fit-up. With a rotating cone on a 25 mm shaft, typical catalogue practice is a k5 shaft seat with an H7 housing bore, EP lubrication and a defined end-play setting — verify against the load direction and magnitude.
Typical equipment & failure modes
Common applications
- agricultural implement wheels
- passenger-car wheel hubs
- small trailer axles
- light differential pinions
- steering knuckles
Known failure patterns
- false brinelling from vibration while the axle is stationary during transport
- fretting corrosion on a loose shaft seat when the cone is pressed to an interference that relaxes with wear
- cup creep and housing bore fretting when the outer ring is left without its specified press fit
- roller large-end smearing and scoring against the inner-ring guide rib from loss of the EP lubricant film
- raceway spalling at the roller-rib junction after the L10 life or sustained axial overload
Selection pitfalls — read before you substitute
- At 25 mm bore the small 30205 is commonly factory-adjusted in a hub unit; an after-market fit-up must reproduce the specified end play (a typical starting range of 0.02–0.10 mm at the 25 mm shaft) or the wheel runs hot within the first hundred kilometres.
- The 302 light series at 25 mm bore (52×16.25 mm, 13.5 mm section) is the default general-purpose tapered row; a 32205 on the same 25 mm bore uses the same OD but a wider section for heavier load — it is not a like-for-like width swap.
- Check the shoulder geometry for 30205: a generous fillet on the 25 mm shaft looks strong but stops the 16.25 mm ring seating home; use the catalogue corner-relief radius and provide a withdrawal groove so the 13.5 mm-section cup presses flush in the 52 mm housing.
- Never fit 30205 by tightening the adjuster to force the cone up the 25 mm taper — draw the nut to seat the rollers, then back it off; the 16.25 mm total width is set by the cup-cone stack, and pushing beyond it is the common cause of seized ribs.
- Keep the 30205 pair matched through rebuilds; the 16.25 mm running geometry and contact pattern are adjusted between the two cups, so replacing one side with an unmarked row shifts the contact patch off-centre and ruins the 25 mm shaft alignment.
- Press the 30205 cone onto the 25 mm shaft with force on the inner ring and the cup into the 52 mm housing on the outer ring; driving through the rollers or transmitting mounting force across the assembly brinells the raceways.
- Do not swap a 30200 row for a ball bearing of the same bore: tapered rollers are heavier, slower (sliding rib contact caps the speed) and must be adjusted, but they outperform ball bearings on combined load and shock in gear and hub duty.
Frequently asked questions
What are the dimensions of a 30205 tapered roller bearing?
A 30205 single-row metric tapered roller bearing per ISO 355 has a 25 mm bore, 52 mm outer diameter and 16.25 mm total assembly width (0.984 × 2.047 × 0.64 in), a 13.5 mm radial section and roughly 135 g geometry-based estimated mass; catalogue masses vary with roller and cage design.
How does the 30205 bore code work?
The last two digits of 30205 are bore code 05, giving 05 × 5 = 25 mm bore — the same convention as 6xx ball bearings, starting at code 04 (20 mm). The 52 mm OD and 16.25 mm width come from the ISO 355 diameter and width series, not the bore code alone.
What is the cone and cup of 30205?
Tapered roller bearings are separable: the cone is the inner ring with the tapered rollers and cage, the cup is the outer ring. 30205 denotes a matched cone-and-cup set. They are fitted separately — cone pressed on the shaft, cup in the housing — and adjusted against each other.
How is the preload or clearance of 30205 set?
At fit-up the 25 mm-bore cone is tightened against the cup while the hub is rotated, seated, then backed off to the specified end play — a typical starting range of 0.02–0.10 mm for a 25 mm bore — and locked with shims, a locknut or a spacer. Too tight overheats and seizes the rib; too loose causes skid, noise and early wear. Confirm the exact figure in the hub or axle-maker procedure.
Can 30205 take axial load in both directions?
A single 30205 takes thrust in one direction only — the roller large ends bear against the inner-ring rib under load. Bidirectional axial load requires an opposed pair: X (face-to-face) tolerates misalignment slightly better, O (back-to-back) gives a wider load centre and more moment stiffness.
Reviewed & verified by the MPN Base engineering desk against source catalog iso355-geometry on 2026-09-24. Read our editorial & correction policy.