32309 bearing: complete specifications & equivalents
The 32309 is a ISO 355 radial bearing sized 45 x 100 x 38.25 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 | 100 mm |
| Width B | 38.25 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) | 1222 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 32309 are being backfilled — use the inquiry form for certified values.
Dimensions in inches & 32300-series range
| Bore d | 1.772 in |
|---|---|
| Outer diameter D | 3.937 in |
| Width B | 1.506 in |
| ISO bore code | 09 |
| Radial section height (D−d)/2 | 27.5 mm |
| Smallest bore in 32300-series | 20 mm |
| Largest outer diameter in 32300-series | 240 mm |
| Width range across 32300-series | 22.25–84.5 mm |
| Bore position in 32300-series (smallest first) | 6 of 19 |
| Bore above smallest 32300-series size | 25 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| 32309 | 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 32309 model number is decoded
In the 32300-series the last two digits of 32309 encode the bore: code 09 = 45 mm (code × 5 from 04 upward). The ISO 355 envelope is 100 mm outside diameter and 38.25 mm total assembly width T over the separable cone and cup — 1.772 × 3.937 × 1.506 in, with a 27.5 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 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
- 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
- fretting corrosion on a loose shaft seat when the cone is pressed to an interference that relaxes with wear
Selection pitfalls — read before you substitute
- On this 45 mm-bore 32309, 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 323 heavy wide series at 45 mm bore (100×38.25 mm) is a steep-angle, high-thrust row for heavy final drives; its 27.5 mm section and 38.25 mm width dwarf the 30209, and its speed ceiling is the lowest of the four series.
- The 38.25 mm-wide 32309 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 100 mm cup seat square — an undercut beats an oversized radius, which lifts the ring and edge-loads the 27.5 mm section.
- When mounting 32309 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 100 mm assembly dents the tapered raceway before first run.
- Relubrication for 32309 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 38.25 mm-wide assembly or the sliding rib contact starves first.
- Tapered rollers accept virtually no misalignment; a deflected 45 mm shaft or a tilted housing shoulder concentrates load on one end of the 38.25 mm-wide roller row — align seats and verify housing perpendicularity.
- Press the 32309 cone onto the 45 mm shaft with force on the inner ring and the cup into the 100 mm housing on the outer ring; driving through the rollers or transmitting mounting force across the assembly brinells the raceways.
Frequently asked questions
What are the dimensions of a 32309 tapered roller bearing?
A 32309 single-row metric tapered roller bearing per ISO 355 has a 45 mm bore, 100 mm outer diameter and 38.25 mm total assembly width (1.772 × 3.937 × 1.506 in), a 27.5 mm radial section and roughly 1222 g geometry-based estimated mass; catalogue masses vary with roller and cage design.
How does the 32309 bore code work?
The last two digits of 32309 are bore code 09, giving 09 × 5 = 45 mm bore — the same convention as 6xx ball bearings, starting at code 04 (20 mm). The 100 mm OD and 38.25 mm width come from the ISO 355 diameter and width series, not the bore code alone.
What is the cone and cup of 32309?
Tapered roller bearings are separable: the cone is the inner ring with the tapered rollers and cage, the cup is the outer ring. 32309 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 32309 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 32309 take axial load in both directions?
A single 32309 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.