32004 bearing: complete specifications & equivalents
The 32004 is a ISO 355 radial bearing sized 20 x 42 x 15 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Bore diameter d | 20 mm |
| Outer diameter D | 42 mm |
| Width B | 15 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) | 82 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 32004 are being backfilled — use the inquiry form for certified values.
Dimensions in inches & 32000-series range
| Bore d | 0.787 in |
|---|---|
| Outer diameter D | 1.654 in |
| Width B | 0.591 in |
| ISO bore code | 04 |
| Radial section height (D−d)/2 | 11 mm |
| Smallest bore in 32000-series | 20 mm |
| Largest outer diameter in 32000-series | 225 mm |
| Width range across 32000-series | 15–48 mm |
| Bore position in 32000-series (smallest first) | 1 of 23 |
| Bore above smallest 32000-series size | 0 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| 32004 | 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 32004 model number is decoded
In the 32000-series the last two digits of 32004 encode the bore: code 04 = 20 mm (code × 5 from 04 upward). The ISO 355 envelope is 42 mm outside diameter and 15 mm total assembly width T over the separable cone and cup — 0.787 × 1.654 × 0.591 in, with a 11.0 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 20 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
- passenger-car wheel hubs
- small trailer axles
- light differential pinions
- steering knuckles
- small gearbox shafts
Known failure patterns
- 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
- 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
Selection pitfalls — read before you substitute
- At 20 mm bore the small 32004 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 20 mm shaft) or the wheel runs hot within the first hundred kilometres.
- The 320 narrow series at 20 mm bore keeps the OD down to 42 mm for space-limited hubs; its 15 mm width carries less load than a 30204, so do not substitute it into a 302 application without re-rating.
- Before fitting 32004, machine the 20 mm shaft seat and 42 mm housing bore with a relief or small fillet so nothing bridges the bearing chamfer; the 15 mm-wide cone and cup only load correctly when the full faces abut, and a large radius pinches the 11.0 mm radial section.
- The 32004 cup drives into the 42 mm housing bore with a sleeve against its outer face only; pressure on the inner ring or cage transfers through the rollers and leaves indentations that become spalls within the 15 mm load zone.
- Keep the 32004 pair matched through rebuilds; the 15 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 20 mm shaft alignment.
- Press the 32004 cone onto the 20 mm shaft with force on the inner ring and the cup into the 42 mm housing on the outer ring; driving through the rollers or transmitting mounting force across the assembly brinells the raceways.
- Do not swap a 32000 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 32004 tapered roller bearing?
A 32004 single-row metric tapered roller bearing per ISO 355 has a 20 mm bore, 42 mm outer diameter and 15 mm total assembly width (0.787 × 1.654 × 0.591 in), a 11.0 mm radial section and roughly 82 g geometry-based estimated mass; catalogue masses vary with roller and cage design.
How does the 32004 bore code work?
The last two digits of 32004 are bore code 04, giving 04 × 5 = 20 mm bore — the same convention as 6xx ball bearings, starting at code 04 (20 mm). The 42 mm OD and 15 mm width come from the ISO 355 diameter and width series, not the bore code alone.
What is the cone and cup of 32004?
Tapered roller bearings are separable: the cone is the inner ring with the tapered rollers and cage, the cup is the outer ring. 32004 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 32004 set?
At fit-up the 20 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 20 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 32004 take axial load in both directions?
A single 32004 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.