32311 bearing: complete specifications & equivalents
The 32311 is a ISO 355 radial bearing sized 55 x 120 x 45.5 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Bore diameter d | 55 mm |
| Outer diameter D | 120 mm |
| Width B | 45.5 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) | 2074 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 32311 are being backfilled — use the inquiry form for certified values.
Dimensions in inches & 32300-series range
| Bore d | 2.165 in |
|---|---|
| Outer diameter D | 4.724 in |
| Width B | 1.791 in |
| ISO bore code | 11 |
| Radial section height (D−d)/2 | 32.5 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) | 8 of 19 |
| Bore above smallest 32300-series size | 35 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| 32311 | 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 32311 model number is decoded
In the 32300-series the last two digits of 32311 encode the bore: code 11 = 55 mm (code × 5 from 04 upward). The ISO 355 envelope is 120 mm outside diameter and 45.5 mm total assembly width T over the separable cone and cup — 2.165 × 4.724 × 1.791 in, with a 32.5 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 55 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
- industrial transmission shafts
- light-truck and van wheel hubs
- final-drive pinion and differential bearings
- commercial gearbox input/output shafts
- conveyor head and tail pulleys
Known failure patterns
- 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
- 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
Selection pitfalls — read before you substitute
- On this 55 mm-bore 32311, 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 55 mm seat can seize hot.
- The 323 heavy wide series at 55 mm bore (120×45.5 mm) is a steep-angle, high-thrust row for heavy final drives; its 32.5 mm section and 45.5 mm width dwarf the 30211, and its speed ceiling is the lowest of the four series.
- Check the shoulder geometry for 32311: a generous fillet on the 55 mm shaft looks strong but stops the 45.5 mm ring seating home; use the catalogue corner-relief radius and provide a withdrawal groove so the 32.5 mm-section cup presses flush in the 120 mm housing.
- Never fit 32311 by tightening the adjuster to force the cone up the 55 mm taper — draw the nut to seat the rollers, then back it off; the 45.5 mm total width is set by the cup-cone stack, and pushing beyond it is the common cause of seized ribs.
- Keep the 32311 pair matched through rebuilds; the 45.5 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 55 mm shaft alignment.
- Do not swap a 32300 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.
- Assign fits by which ring rotates: an interference shaft fit for a rotating cone; if the cup rotates instead, reverse the logic — a loose rotating ring creeps and frets its seat.
Frequently asked questions
What are the dimensions of a 32311 tapered roller bearing?
A 32311 single-row metric tapered roller bearing per ISO 355 has a 55 mm bore, 120 mm outer diameter and 45.5 mm total assembly width (2.165 × 4.724 × 1.791 in), a 32.5 mm radial section and roughly 2074 g geometry-based estimated mass; catalogue masses vary with roller and cage design.
How does the 32311 bore code work?
The last two digits of 32311 are bore code 11, giving 11 × 5 = 55 mm bore — the same convention as 6xx ball bearings, starting at code 04 (20 mm). The 120 mm OD and 45.5 mm width come from the ISO 355 diameter and width series, not the bore code alone.
What is the cone and cup of 32311?
Tapered roller bearings are separable: the cone is the inner ring with the tapered rollers and cage, the cup is the outer ring. 32311 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 32311 set?
At fit-up the 55 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 55 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 32311 take axial load in both directions?
A single 32311 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.