61908-RSR bearing: complete specifications & equivalents
The 61908-RSR is a ISO 15 radial bearing sized 40 x 62 x 12 mm (bore x OD x width) with RSR sealing. Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | SKF |
| Bore diameter d | 40 mm |
| Outer diameter D | 62 mm |
| Width B | 12 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 | 13.8 kN |
| Basic static load rating C0 | 10 kN |
| Fatigue load limit Pu | 0.425 kN |
| Reference speed (thermal) | 24000 rpm |
| Limiting speed (mechanical) | 12000 rpm |
| Operating temperature | -30 to +120 °C |
| Mass | 120 g |
| Manufacturer designation | SKF 61908-2RZ |
| 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 & 61900-series range
| Bore d | 1.575 in |
|---|---|
| Outer diameter D | 2.441 in |
| Width B | 0.472 in |
| ISO bore code | 08 |
| Radial section height (D−d)/2 | 11 mm |
| Smallest bore in 61900-series | 3 mm |
| Largest outer diameter in 61900-series | 1120 mm |
| Width range across 61900-series | 3–118 mm |
| Bore position in 61900-series (smallest first) | 16 of 63 |
| Bore above smallest 61900-series size | 37 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| 61908-2RS-FAG | FAG | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 40×62×12 mm envelope per ISO 15; seal variant differs (RSR vs 2RS) — confirm sealing suits the duty. |
| 61908-FAG | FAG | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 40×62×12 mm envelope per ISO 15; seal variant differs (RSR vs OPEN) — confirm sealing suits the duty. |
| 61908-2RS-NSK | NSK | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 40×62×12 mm envelope per ISO 15; seal variant differs (RSR vs 2RS) — confirm sealing suits the duty. |
| 61908-NSK | NSK | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 40×62×12 mm envelope per ISO 15; seal variant differs (RSR vs OPEN) — confirm sealing suits the duty. |
| 61908-RSR-NSK | NSK | 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. |
| 61908-ZZ | NSK | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 40×62×12 mm envelope per ISO 15; seal variant differs (RSR vs ZZ) — confirm sealing suits the duty. |
| 61908-2RS-NTN | NTN | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 40×62×12 mm envelope per ISO 15; seal variant (RSR vs 2RS) and load ratings differ — confirm sealing and rating before substituting. |
| 61908-NTN | NTN | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 40×62×12 mm envelope per ISO 15; seal variant (RSR vs OPEN) and load ratings differ — confirm sealing and rating before substituting. |
| 61908-RSR-NTN | NTN | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 40×62×12 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting. |
| 61908-ZZ-NTN | NTN | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 40×62×12 mm envelope per ISO 15; seal variant (RSR vs ZZ) and load ratings differ — confirm sealing and rating before substituting. |
| W61908-2RS | SKF | partial Main dimensions match; tolerances, seals or internal clearance differ. | SKF stainless execution W 61908-2RS1 shares the 40×62×12 mm envelope but rates differently (13.8/10 kN vs 11.9/9.8 kN) — not a load-rating equivalent. |
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 61908-RSR model number is decoded
In the 61900-series (diameter series 9 of ISO 15) the last two digits encode the bore: 61908 carries bore code 08 = 40 mm. Outside diameter 62 mm and width 12 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. SKF's low-friction seal suffix is 2RSL/2RZ (this page's industry-neutral spelling is -RSR); catalogue number 61908-2RZ.
Typical equipment & failure modes
Common applications
- space-constrained gearboxes
- clutch and transmission assemblies
- robotics and automation joints
- lay shafts and idler shafts
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
- rolling-contact fatigue spalling after the rated L10 life is exceeded
- brinelling from static overload or hammering during mounting
Selection pitfalls — read before you substitute
- Sizes around 40 mm bore are normally pressed on cold with a sleeve against the inner-ring face; the press force must never route through the outer ring or the balls of 61908-RSR.
- The 619xx thin section at 40 mm bore (11.0 mm section height) cannot shrug off the misalignment a standard section tolerates; keep the housing bores round and aligned, or edge contact will spall the raceways early.
- RSR low-friction seals on 61908-RSR run faster than contact-seal 61908-2RS but let fine dust and moisture past the non-contact lip; in dirty or wet duty specify 61908-2RS instead.
- The non-contact lip of 61908-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.
- Deep-groove ball bearings tolerate only minutes of misalignment; if the 62 mm housing cannot be aligned, switch to a self-aligning type rather than shimming 61908-RSR.
- Axial location must clamp the ring face, not the seal area: a shoulder or circlip bearing on the seal side of the 12 mm-wide ring of 61908-RSR drags the lip and overheats it.
- SKF catalogues the low-friction seal as 61908-2RZ (suffix -2RSL or -2RZ): a non-contact elastomer lip that runs near the open 12000 r/min limiting speed, closer to the open bearing's 24000 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 13.8/10 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 61908-RSR bearing?
A 61908-RSR deep-groove ball bearing has a 40 mm bore, 62 mm outer diameter and 12 mm width (1.575 × 2.441 × 0.472 in), per ISO 15 boundary dimensions. It is fitted with two low-friction non-contact rubber seals.
What lubrication does 61908-RSR need?
61908-RSR is supplied pre-greased for life and is not designed to be opened for relubrication; where a relubrication path is required, specify the open 61908 with a housing grease fitting instead.
How does the 61908 bore code work?
The last two digits of 61908 are bore code 08, giving 08 × 5 = 40 mm bore. The 62 mm outside diameter and 12 mm width follow the ISO 15 diameter series, not the bore code alone.
What does the RSR suffix on 61908-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.
What is the SKF designation and catalogue data for 61908-RSR?
In the SKF Rolling Bearings catalogue this size is listed as 61908-2RZ — two low-friction non-contact elastomer seals, 40×62×12 mm per ISO 15. Quoted values: C 13.8 kN, C0 10 kN, Pu 0.425 kN, limiting speed 12000 r/min, mass 120 g. Brand suffixes (2Z, 2RSH, 2RSL) differ from the industry-neutral spelling 61908-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.