30209 bearing: complete specifications & equivalents
The 30209 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 |
|---|---|
| Bore diameter d | 45 mm |
| Outer diameter D | 85 mm |
| Width B | 20.75 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) | 432 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 30209 are being backfilled — use the inquiry form for certified values.
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 | 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) | 6 of 19 |
| Bore above smallest 30200-series size | 25 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| 30209 | 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 30209 model number is decoded
In the 30200-series the last two digits of 30209 encode the bore: code 09 = 45 mm (code × 5 from 04 upward). The ISO 355 envelope is 85 mm outside diameter and 20.75 mm total assembly width T over the separable cone and cup — 1.772 × 3.346 × 0.817 in, with a 20.0 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 45 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
- conveyor head and tail pulleys
- fork-lift steer axles
- industrial transmission shafts
- light-truck and van wheel hubs
- final-drive pinion and differential bearings
Known failure patterns
- raceway spalling at the roller-rib junction after the L10 life or sustained axial overload
- over-preload heat: a shim stack cut too thin drives contact stress up and seizes the cone on the seat
- under-preload end play that lets the rollers skid, producing noise and false brinelling
- water and grit pitting in unsealed hubs where the cup-cone joint acts as a debris entry path
- false brinelling from vibration while the axle is stationary during transport
Selection pitfalls — read before you substitute
- On this 45 mm-bore 30209, thermal growth of the shaft closes up the adjusted clearance; set cold end play around 0.03–0.12 mm and recheck after the first hot run — a medium-series cone that was correct cold on the 45 mm seat can seize hot.
- The 302 light series at 45 mm bore (85×20.75 mm, 20.0 mm section) is the default general-purpose tapered row; a 32209 on the same 45 mm bore uses the same OD but a wider section for heavier load — it is not a like-for-like width swap.
- The 20.75 mm-wide 30209 ring seats against a shaft and housing shoulder whose fillet must clear the bearing chamfer: keep the corner radius small enough that the 45 mm bore and 85 mm cup seat square — an undercut beats an oversized radius, which lifts the ring and edge-loads the 20.0 mm section.
- When mounting 30209 to a 45 mm shaft, warm the cone to 80–100 °C and slide it dry to the shoulder; cooling shrinks it into its interference, whereas hammering a cold cone through a 85 mm assembly dents the tapered raceway before first run.
- Relubrication for 30209 must reach the rib-roller end contact, not just the 45 mm bore; in a hub repack, work EP grease through the roller set until it exudes at both faces of the 20.75 mm-wide assembly or the sliding rib contact starves first.
- The cone and the cup of 30209 are separable: order and fit them as a matched set; never mix a cone from one manufacturer with another brand's cup — roller geometry and contact angle are not identical across brands.
- Set running clearance (or preload) with the shim pack or adjusting nut at fit-up; a 45 mm-bore 30209 that is too tight overheats and scores the rib, one too loose develops end play and noise — follow the torque-and-untighten procedure.
Frequently asked questions
What are the dimensions of a 30209 tapered roller bearing?
A 30209 single-row metric tapered roller bearing per ISO 355 has a 45 mm bore, 85 mm outer diameter and 20.75 mm total assembly width (1.772 × 3.346 × 0.817 in), a 20.0 mm radial section and roughly 432 g geometry-based estimated mass; catalogue masses vary with roller and cage design.
How does the 30209 bore code work?
The last two digits of 30209 are bore code 09, giving 09 × 5 = 45 mm bore — the same convention as 6xx ball bearings, starting at code 04 (20 mm). The 85 mm OD and 20.75 mm width come from the ISO 355 diameter and width series, not the bore code alone.
What is the cone and cup of 30209?
Tapered roller bearings are separable: the cone is the inner ring with the tapered rollers and cage, the cup is the outer ring. 30209 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 30209 set?
At fit-up the 45 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 0.03–0.12 mm for a 45 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 30209 take axial load in both directions?
A single 30209 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.