33020 bearing: complete specifications & equivalents
The 33020 is a ISO 355 radial bearing sized 100 x 150 x 39 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | SKF |
| Bore diameter d | 100 mm |
| Outer diameter D | 150 mm |
| Width B | 39 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | steel, stamped ribbon (J-type) |
| Basic dynamic load rating C | 278 kN |
| Basic static load rating C0 | 390 kN |
| Fatigue load limit Pu | 41.5 kN |
| Reference speed (thermal) | 3400 rpm |
| Limiting speed (mechanical) | 4000 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 2400 g |
| Manufacturer designation | SKF 33020 |
| 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 & 33000-series range
| Bore d | 3.937 in |
|---|---|
| Outer diameter D | 5.906 in |
| Width B | 1.535 in |
| ISO bore code | 20 |
| Radial section height (D−d)/2 | 25 mm |
| Smallest bore in 33000-series | 50 mm |
| Largest outer diameter in 33000-series | 225 mm |
| Width range across 33000-series | 24–59 mm |
| Bore position in 33000-series (smallest first) | 11 of 16 |
| Bore above smallest 33000-series size | 50 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| 33020 | ISO 15 | full Dimensions and internal design equivalent — standard interchange. | ISO 355 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 33020 model number is decoded
SKF 33020 belongs to the SKF single-row tapered roller range — the 100 mm bore entry in the 33000 series, dimensioned 150 mm OD and 39 mm wide to the ISO 355 boundary plan.Digit by digit, 33020 reads as bearing type 3 (single-row tapered roller), slim light section series 30, and bore reference 20 resolving to 100 mm; 150 mm OD and 39 mm width are the matching ISO 355 boundary values. The SKF catalogue adds the ISO 355 dimension-series code after the bare number (e.g. 2CE); it is the dimensional series, not a separate part number. The 25.0 mm radial section height ((150−100)/2) and 2400 g catalogue mass frame a 100 mm bore bearing rated at 278 kN C — roughly 2.78 kN of dynamic capacity per millimetre of bore before application factors. Because the contact line is tapered, one 33020 reacts thrust in a single direction; bidirectional shafts need an O or X pair, and a rotating cone on a 100 mm shaft typically takes a k5 seat with an H7 housing bore.
Typical equipment & failure modes
Common applications
- rolling-mill auxiliary drives
- crane sheave and hoist gearboxes
- paper-machine and printing rolls
- construction machinery drives
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
- thermal preload runaway in an O-arrangement pair when inner-ring heat expands the setting
- uneven load sharing in a pair when spacer faces are not parallel to the bore
- cage pocket scoring when the bearing starts cold with grease of too-high base-oil viscosity
- brinelling from pressing the cone or cup home through the rollers
Selection pitfalls — read before you substitute
- Mount the 100 mm bore 33020 by induction heating of the cone (max 120 °C — the pressed-steel cage sets the ceiling, not the steel); driving it home through the cup or rollers brinells the tapered raceway.
- The 330 series at 100 mm bore (150×39 mm) is the slim-OD envelope: it buys radial space but gives up capacity against a 30220 of the same bore — confirm the L10 margin before downsizing into it.
- A single 33020 cannot locate the shaft axially in both directions; mounting it singly on a reversing-thrust shaft leaves one direction uncontrolled — always use an O or X matched pair for bidirectional location.
- When the outer ring rotates, reverse the fit logic and provide cup location; the tapered contact of 33020 pushes the rings apart under load, so a non-located cup walks its seat even when the shaft is fixed.
- Never press both rings through the wrong element during fitting: force for an interference shaft seat goes through the cone only, or brinell marks on the 150 mm cup race release as noise within the first running hours.
- The 278/390 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 33020 (basic, B steeper angle, Q/J2 clearance variants); they are not interchangeable order numbers — quote the full SKF 33020 designation when purchasing and match the execution to the mounting arrangement.
Frequently asked questions
What are the dimensions and catalogue data of 33020?
The SKF 33020 is a single-row tapered roller bearing with 100 mm bore, 150 mm outer diameter and 39 mm width (3.937 × 5.906 × 1.535 in) per ISO 355. From SKF catalogue PUB BU/P1 17000: basic dynamic load rating C 278 kN, C0 390 kN, fatigue load limit Pu 41.5 kN, reference speed 3,400 r/min, limiting speed 4,000 r/min, mass about 2400 g. It is an open, separable bearing with a pressed-steel cage.
How does the 33020 bore code work?
The last two digits of 33020 are bore code 20, so 20 × 5 = 100 mm bore. The 150 mm OD and 39 mm width come from the ISO 355 dimension-series plan, shared with other tapered bearings of the same code.
What do the 33020 series and basic execution designations mean?
The leading 3 marks a single-row tapered roller bearing; the second digit 30 is the ISO 355 series (slim light 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 33020 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 33020 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 33020 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.