30211 bearing: complete specifications & equivalents
The 30211 is a ISO 355 radial bearing sized 55 x 100 x 22.75 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | SKF |
| Bore diameter d | 55 mm |
| Outer diameter D | 100 mm |
| Width B | 22.75 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | steel, stamped ribbon (J-type) |
| Basic dynamic load rating C | 111 kN |
| Basic static load rating C0 | 106 kN |
| Fatigue load limit Pu | 12 kN |
| Reference speed (thermal) | 5300 rpm |
| Limiting speed (mechanical) | 6700 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 700 g |
| Manufacturer designation | SKF 30211 |
| Standard | ISO 355 |
| Catalog version | SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 8.1 metric single-row TRB |
| Last verified | 2026-09-26 |
Source: catalog reference (SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 8.1 metric single-row TRB) · extracted 2026-09-26
Parameters extracted from the official SKF Rolling Bearings catalogue (SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 8.1 metric single-row TRB); SKF® and SKF Explorer® are trademarks of AB SKF, used here for identification only — mpnbase is not an authorized SKF distributor. Boundary dimensions are ISO 15 interchangeable; current production values may differ, verify at skf.com.
Dimensions in inches & 30200-series range
| Bore d | 2.165 in |
|---|---|
| Outer diameter D | 3.937 in |
| Width B | 0.896 in |
| ISO bore code | 11 |
| Radial section height (D−d)/2 | 22.5 mm |
| Smallest bore in 30200-series | 15 mm |
| Largest outer diameter in 30200-series | 580 mm |
| Width range across 30200-series | 11.75–104 mm |
| Bore position in 30200-series (smallest first) | 11 of 37 |
| Bore above smallest 30200-series size | 40 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| 30211 | ISO 15 | full Dimensions and internal design equivalent — standard interchange. | ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier. |
| 30211-NTN | NTN | full Dimensions and internal design equivalent — standard interchange. | Identical ISO 15 envelope, seal and ratings band — standard interchange; re-verify precision class and clearance per supplier. |
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 30211 model number is decoded
For a 55 mm shaft carrying combined load, SKF lists 30211 under catalogue execution SKF 30211: one open single-row tapered roller bearing in the standard section of the 30200 family.The code breaks down as type prefix 3 (tapered roller), series 0 (the standard section), and bore code 11 = 55 mm; dimensions 55×100×22.75 mm therefore match the ISO 355 envelope. SKF lists the plain number as the basic execution; letter suffixes such as B denote a steeper contact angle and are different order numbers. The 22.5 mm radial section height ((100−55)/2) and 700 g catalogue mass frame a 55 mm bore bearing rated at 111 kN C — roughly 2.02 kN of dynamic capacity per millimetre of bore before application factors. Note the minimum-axial-load requirement: at light radial load and high speed the rollers of 30211 must still be held into the rib contact, which is another reason the catalogue recommends paired mounting with controlled setting.
Typical equipment & failure modes
Common applications
- differential and pinion drives
- pump and compressor shafts
- machine-tool spindles
- belt-driven fan and blower shafts
Known failure patterns
- cup or cone misalignment when the separable rings are not seated square during mounting
- loose cup rotation in the housing when the specified press fit is not achieved
- axial overload spalling at the roller-rib contact beyond the single-row thrust rating
- preload loss as the mounted pair relaxes, letting rollers skid and smear the raceways
- pressed-steel cage wear or fracture after prolonged running above the limiting speed
- rolling-contact fatigue spalling after the rated L10 life is exceeded
Selection pitfalls — read before you substitute
- On this 55 mm bore, interference and temperature rise consume clearance inside a preloaded pair; calculate the residual clearance after mounting and at operating temperature — an over-tight 30211 pair heats, loses setting control and smears the roller-rib contact.
- The 302 series at 55 mm bore (100×22.75 mm) is the standard tapered-roller envelope; stepping to a 32211 or 32311 changes OD, width and heat generation — it is not a drop-in swap when the housing and speed are fixed.
- When the outer ring rotates, reverse the fit logic and provide cup location; the tapered contact of 30211 pushes the rings apart under load, so a non-located cup walks its seat even when the shaft is fixed.
- The tapered contact angle creates an induced axial load under pure radial force; include it in the 30211 rating calculation (and account for it in both bearings of a pair) or the unloaded bearing skids its rollers.
- The 30211 shares its ISO 355 envelope with other tapered bearings of the same code but is not a drop-in replacement for a ball bearing: it cannot run effectively under pure radial load without a minimum axial load, and a deep-groove bearing cannot replace its combined-load duty.
- The 111/106 kN ratings are SKF catalogue 17000 values for the basic execution; SKF can revise internal geometry without changing the order number, so keep the catalogue version (PUB BU/P1 17000/1 EN, 2018) with the specification and re-verify for critical drives.
- SKF lists several executions of 30211 (basic, B steeper angle, Q/J2 clearance variants); they are not interchangeable order numbers — quote the full SKF 30211 designation when purchasing and match the execution to the mounting arrangement.
Frequently asked questions
What are the dimensions and catalogue data of 30211?
The SKF 30211 is a single-row tapered roller bearing with 55 mm bore, 100 mm outer diameter and 22.75 mm width (2.165 × 3.937 × 0.896 in) per ISO 355. From SKF catalogue PUB BU/P1 17000: basic dynamic load rating C 111 kN, C0 106 kN, fatigue load limit Pu 12 kN, reference speed 5,300 r/min, limiting speed 6,700 r/min, mass about 700 g. It is an open, separable bearing with a pressed-steel cage.
How does the 30211 bore code work?
The last two digits of 30211 are bore code 11, so 11 × 5 = 55 mm bore. The 100 mm OD and 22.75 mm width come from the ISO 355 dimension-series plan, shared with other tapered bearings of the same code.
What do the 30211 series and basic execution designations mean?
The leading 3 marks a single-row tapered roller bearing; the second digit 0 is the ISO 355 series (standard section). The SKF catalogue lists the ISO 355 dimension-series code after the bare number. A steeper-contact-angle variant (B suffix) is a different order number and is not interchangeable with the basic execution.
Can a single 30211 take axial load in both directions?
No — one single-row tapered roller bearing reacts thrust in one direction only, and under radial load its contact angle induces an axial force. Use two bearings as a matched pair: O (back-to-back) for a rigid, moment-resisting arrangement, X (face-to-face) where thermal expansion must be tolerated, or tandem where one-direction thrust is shared.
How does 30211 compare with a ball bearing of the same bore?
A tapered roller bearing has line contact and a steep contact angle: much higher combined axial-plus-radial capacity and shock resistance than a ball bearing of the same bore, at the cost of speed, one-direction thrust, mandatory pairing for reversing loads and a minimum axial load requirement. A ball bearing cannot be dropped into a combined-load 30211 position and vice versa — verify load direction, Fa/Fr ratio and speed before substituting.
Reviewed & verified by the MPN Base engineering desk against source catalog SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 8.1 metric single-row TRB on 2026-09-26. Read our editorial & correction policy.