61808-RSR bearing: complete specifications & equivalents
The 61808-RSR is a ISO 15 radial bearing sized 40 x 52 x 7 mm (bore x OD x width) with RSR sealing. Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Bore diameter d | 40 mm |
| Outer diameter D | 52 mm |
| Width B | 7 mm |
| Material | GCr15 |
| Seal / shield | RSR |
| Internal clearance | CN / C3 available |
| Tolerance class | P0 |
| Cage | steel, stamped ribbon (J-type) |
| Basic dynamic load rating C | 4.49 kN |
| Basic static load rating C0 | 3.75 kN |
| Fatigue load limit Pu | 0.16 kN |
| Reference speed (thermal) | 26000 rpm |
| Limiting speed (mechanical) | 13000 rpm |
| Operating temperature | -30 to +120 °C |
| Mass | 34 g |
| Manufacturer designation | SKF 61808-2RZ |
| Standard | ISO 15 |
| Catalog version | SKF PUB BU/P1 17000/1 EN (Oct 2018) |
| Last verified | 2026-09-24 |
Source: catalog reference (SKF PUB BU/P1 17000/1 EN (Oct 2018)) · extracted 2026-09-24
Parameters extracted from the official SKF Rolling Bearings catalogue (SKF PUB BU/P1 17000/1 EN (Oct 2018)); 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 & 61800-series range
| Bore d | 1.575 in |
|---|---|
| Outer diameter D | 2.047 in |
| Width B | 0.276 in |
| ISO bore code | 08 |
| Radial section height (D−d)/2 | 6 mm |
| Smallest bore in 61800-series | 10 mm |
| Largest outer diameter in 61800-series | 420 mm |
| Width range across 61800-series | 5–38 mm |
| Bore position in 61800-series (smallest first) | 9 of 39 |
| Bore above smallest 61800-series size | 30 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| 61808-ZZ | GENERIC-ISO | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 40×52×7 mm envelope per ISO 15; seal variant differs (RSR vs ZZ) — confirm sealing suits the duty. |
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 61808-RSR model number is decoded
In the 61800-series (ISO 15 diameter series 8) the last two digits encode the bore: 61808 carries bore code 08 = 40 mm. Outside diameter 52 mm and width 7 mm come from the ISO 15 boundary-dimensions general plan. Suffix -RSR denotes two low-friction non-contact elastomer seals; they keep coarse debris out with minimal drag but are not liquid-tight. For normal-load mounting with a rotating inner ring on a 40 mm shaft, typical catalogue practice is a k5 shaft seat with an H7 housing bore — verify against the actual load direction and magnitude.
Typical equipment & failure modes
Common applications
- textile machinery
- packaging machinery
- space-constrained gearboxes
- clutch and transmission assemblies
Known failure patterns
- ingress of fine dust or moisture past the non-contact lip in dirty or wet duty (RSR is not liquid-tight)
- lip-lubricant starvation if the bearing runs dry for extended periods
- electrical pitting in VFD-driven motors without grounding protection
- raceway smearing under marginal lubrication at start-up
Selection pitfalls — read before you substitute
- At a 40 mm bore, a shaft-seat burr or an overtight setscrew can score the thin inner ring of 61808-RSR; check shaft finish and runout (target Ra ≤ 1.6 µm) before pressing it home.
- The 618xx thin section at 40 mm bore has only a 6.0 mm radial section height: it saves space but is highly sensitive to misalignment, shaft deflection and shock loads — verify shaft stiffness before choosing it over a 6208.
- RSR low-friction seals on 61808-RSR run faster than contact-seal 61808-2RS but let fine dust and moisture past the non-contact lip; in dirty or wet duty specify 61808-2RS instead.
- The non-contact lip of 61808-RSR does not retain a lifetime grease fill the way a contact seal does; confirm the regreasing interval for the 40 mm bore position before relying on it as sealed-for-life.
- Shaft and housing fillets must clear the bearing chamfer so the 7 mm-wide ring seats square; provide an undercut or withdrawal groove instead of relying on an oversized radius.
- SKF catalogues the low-friction seal as 61808-2RZ (suffix -2RSL or -2RZ): a non-contact elastomer lip that runs near the open 13000 r/min limiting speed, closer to the open bearing's 26000 r/min reference than the contact-seal version. It keeps coarse debris out without the drag of a contact seal, but is not liquid-tight — use 2RSH for wet or fine-dust positions.
- The 4.49/3.75 kN ratings here are SKF Explorer-class figures from catalogue PUB BU/P1 17000/1 EN (Oct 2018); SKF can revise internal geometry and ratings without changing the designation, so treat the catalogue version and date as part of the specification and re-verify for critical drives.
Frequently asked questions
What are the dimensions of a 61808-RSR bearing?
A 61808-RSR deep-groove ball bearing has a 40 mm bore, 52 mm outer diameter and 7 mm width (1.575 × 2.047 × 0.276 in), per ISO 15 boundary dimensions. It is fitted with two low-friction non-contact rubber seals.
How does the 61808 bore code work?
The last two digits of 61808 are bore code 08, giving 08 × 5 = 40 mm bore. The 52 mm outside diameter and 7 mm width follow the ISO 15 diameter series, not the bore code alone.
What does the RSR suffix on 61808-RSR mean?
RSR means two low-friction non-contact rubber seals. They keep coarse debris out with minimal drag (speed close to the open bearing) but are not liquid-tight; use -2RS contact seals for wet or fine-dust environments.
How does the 61800 compare with other series at the same 40 mm bore?
618 is an extra-thin section: 52×7 mm, only 6.0 mm radial section at 40 mm bore, far smaller than a 6208, for space-limited layouts at the cost of load rating and misalignment tolerance.
What is the SKF designation and catalogue data for 61808-RSR?
In the SKF Rolling Bearings catalogue this size is listed as 61808-2RZ — two low-friction non-contact elastomer seals, 40×52×7 mm per ISO 15. Quoted values: C 4.49 kN, C0 3.75 kN, Pu 0.16 kN, limiting speed 13000 r/min, mass 34 g. Brand suffixes (2Z, 2RSH, 2RSL) differ from the industry-neutral spelling 61808-RSR.
Reviewed & verified by the MPN Base engineering desk against source catalog SKF PUB BU/P1 17000/1 EN (Oct 2018) on 2026-09-24. Read our editorial & correction policy.