30208R bearing: complete specifications & equivalents
The 30208R is a ISO 355 radial bearing sized 40 x 80 x 19.75 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | SKF |
| Bore diameter d | 40 mm |
| Outer diameter D | 80 mm |
| Width B | 19.75 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | steel, stamped ribbon (J-type) |
| Basic dynamic load rating C | 75.8 kN |
| Basic static load rating C0 | 68 kN |
| Fatigue load limit Pu | 7.65 kN |
| Reference speed (thermal) | 7000 rpm |
| Limiting speed (mechanical) | 8500 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 440 g |
| Manufacturer designation | SKF 30208 R |
| Standard | ISO 355 |
| Catalog version | SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 8.3-8.8 TRB variants |
| Last verified | 2026-09-29 |
Source: catalog reference (SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 8.3-8.8 TRB variants) · extracted 2026-09-29
Parameters extracted from the official SKF Rolling Bearings catalogue (SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 8.3-8.8 TRB variants); 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 & flanged-series range
| Bore d | 1.575 in |
|---|---|
| Outer diameter D | 3.15 in |
| Width B | 0.778 in |
| ISO bore code | — |
| Radial section height (D−d)/2 | 20 mm |
| Smallest bore in flanged-series | 35 mm |
| Largest outer diameter in flanged-series | 140 mm |
| Width range across flanged-series | 19–45.5 mm |
| Bore position in flanged-series (smallest first) | 2 of 5 |
| Bore above smallest flanged-series size | 5 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| 30208 | SKF | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same d/D/T boundary as the plain single-row base bearing, but the flanged cup changes housing location — not a drop-in substitute where the flange is the axial register. |
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 30208R model number is decoded
SKF 30208 R belongs to the SKF flanged tapered-roller range — the 40 mm bore entry dimensioned 80×19.75 mm, intended for housings where one side has no room for a turned abutment shoulder.Reading the designation: the leading digits 30208 follow the ISO 355 single-row tapered-roller convention (type 3, dimension series, bore code for the 40 mm bore), and the trailing letter marks the flanged outer ring execution — the boundary dimensions 40×80×19.75 mm match the plain-bearing plan, the flange adds only axial location. Where the flange earns its keep: through-bored housings, sheet-metal or cast covers, and split housings where a machined shoulder would be awkward — the 80 mm cup with its flange locates axially without extra parts. With C 75.8 kN and C0 68 kN, the 30208R sizing check is dominated by the axial share: keep the equivalent load P below the rating at the required L10, remembering the tapered contact induces an axial component under radial load. Dimensional interchange map: within its boundary plan the 40×80×19.75 mm envelope of 30208R is fixed, so shoulder, spacer and seal drawings can be dimensioned straight from the catalogue table. Reversing-thrust shafts need a second tapered bearing facing 30208R; the flange handles location on one side only, it does not make the bearing a double-direction unit.
Typical equipment & failure modes
Common applications
- differential and pinion drives
- pump and compressor shafts
- machine-tool spindles
- differential and pinion drives
Known failure patterns
- roller large-end smearing against the cone rib after EP lubricant film failure
- roller large-end smearing against the cone rib after EP lubricant film failure
- cage pocket scoring when the bearing starts cold with grease of too-high base-oil viscosity
- hard-particle indentation of the tapered raceway in unfiltered oil
- brinelling from pressing the cone or cup home through the rollers
Selection pitfalls — read before you substitute
- Check housing face runout where the flange seats: a face out of square cocks the 19.75 mm-wide cup and concentrates load on one rib — the usual root cause of early flanged-bearing noise.
- The flange does not change the one-direction thrust rule: 30208R still needs a second tapered bearing facing it on reversing-thrust shafts, with the running clearance set at mounting.
- Do not press 30208R home through the rollers: mounting force for the 40 mm bore seat goes through the cone face only, and the flanged cup is located by its flange, not by pressing the 80 mm OD.
- The 75.8/68 kN ratings are SKF catalogue 17000 values for this 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.
- Quote the full SKF 30208 R designation when purchasing — base-number-only orders are ambiguous across executions and variants.
Frequently asked questions
What are the dimensions and catalogue data of 30208R?
The SKF 30208 R is a single-row tapered roller bearing with a flanged outer ring with 40 mm bore, 80 mm outer diameter and 19.75 mm overall width (1.575 × 3.15 × 0.778 in). From SKF catalogue PUB BU/P1 17000: basic dynamic load rating C 75.8 kN, C0 68 kN, fatigue load limit Pu 7.65 kN, reference speed 7,000 r/min, limiting speed 8,500 r/min, mass about 0.44 kg.
What does the flanged outer ring on 30208R do?
The cup of 30208R carries an integral flange that locates the bearing axially against the housing face, so the housing needs no machined abutment shoulder on the flange side. It simplifies through-bored or cover-mounted housings; the running clearance is still set by cone-versus-cup position at mounting, exactly as for the plain 30208 bearing.
Is 30208R interchangeable with the plain 30208 bearing?
The boundary dimensions 40×80×19.75 mm match the ISO 355 plan of the base bearing, but the flanged cup is a different order number. It is interchangeable only where the housing provides axial location by other means; where the flange is the locating feature, a plain cup cannot substitute.
Can a single 30208R take axial load in both directions?
No — like any single-row tapered roller bearing it 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 or X arrangement) for reversing thrust.
What shaft and housing fits suit 30208R?
For a rotating cone on the 40 mm shaft, use a k5 seat; the flanged cup is retained through the flange, so the 80 mm OD seat can be a loose-to-transition fit. Keep housing face runout square so the flange seats without tilting the cup.
Reviewed & verified by the MPN Base engineering desk against source catalog SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 8.3-8.8 TRB variants on 2026-09-29. Read our editorial & correction policy.