30221 bearing: complete specifications & equivalents
The 30221 is a ISO 355 radial bearing sized 105 x 190 x 39 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Bore diameter d | 105 mm |
| Outer diameter D | 190 mm |
| Width B | 39 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) | 3919 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 30221 are being backfilled — use the inquiry form for certified values.
Dimensions in inches & 30200-series range
| Bore d | 4.134 in |
|---|---|
| Outer diameter D | 7.48 in |
| Width B | 1.535 in |
| ISO bore code | 21 |
| Radial section height (D−d)/2 | 42.5 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) | 18 of 19 |
| Bore above smallest 30200-series size | 85 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| 30221 | 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 30221 model number is decoded
In the 30200-series the last two digits of 30221 encode the bore: code 21 = 105 mm (code × 5 from 04 upward). The ISO 355 envelope is 190 mm outside diameter and 39 mm total assembly width T over the separable cone and cup — 4.134 × 7.48 × 1.535 in, with a 42.5 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 105 mm shaft, typical catalogue practice is a m6 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
- crane travel wheels and winch drums
- railway axle boxes
- agricultural tractor axles
- truck and trailer wheel hubs
- heavy final drives and differentials
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
- The large 105 mm-bore 30221 develops substantial mounting forces; heat the cone (induction heater, max 120 °C) and never tighten the adjusting nut to seat it — draw it up by torque, then back off to the mark, leaving roughly 0.05–0.20 mm end play on the 105 mm shaft.
- The 302 light series at 105 mm bore (190×39 mm, 42.5 mm section) is the default general-purpose tapered row; a 32221 on the same 105 mm bore uses the same OD but a wider section for heavier load — it is not a like-for-like width swap.
- The 39 mm-wide 30221 ring seats against a shaft and housing shoulder whose fillet must clear the bearing chamfer: keep the corner radius small enough that the 105 mm bore and 190 mm cup seat square — an undercut beats an oversized radius, which lifts the ring and edge-loads the 42.5 mm section.
- When mounting 30221 to a 105 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 190 mm assembly dents the tapered raceway before first run.
- Relubrication for 30221 must reach the rib-roller end contact, not just the 105 mm bore; in a hub repack, work EP grease through the roller set until it exudes at both faces of the 39 mm-wide assembly or the sliding rib contact starves first.
- Press the 30221 cone onto the 105 mm shaft with force on the inner ring and the cup into the 190 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 30221 tapered roller bearing?
A 30221 single-row metric tapered roller bearing per ISO 355 has a 105 mm bore, 190 mm outer diameter and 39 mm total assembly width (4.134 × 7.48 × 1.535 in), a 42.5 mm radial section and roughly 3919 g geometry-based estimated mass; catalogue masses vary with roller and cage design.
How does the 30221 bore code work?
The last two digits of 30221 are bore code 21, giving 21 × 5 = 105 mm bore — the same convention as 6xx ball bearings, starting at code 04 (20 mm). The 190 mm OD and 39 mm width come from the ISO 355 diameter and width series, not the bore code alone.
What is the cone and cup of 30221?
Tapered roller bearings are separable: the cone is the inner ring with the tapered rollers and cage, the cup is the outer ring. 30221 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 30221 set?
At fit-up the 105 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 0.05–0.20 mm for a 105 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 30221 take axial load in both directions?
A single 30221 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.