61918-RSR bearing: complete specifications & equivalents
The 61918-RSR is a ISO 15 radial bearing sized 90 x 125 x 18 mm (bore x OD x width) with RSR sealing. Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | NSK |
| Bore diameter d | 90 mm |
| Outer diameter D | 125 mm |
| Width B | 18 mm |
| Material | GCr15 |
| Seal / shield | RSR |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | steel |
| Basic dynamic load rating C | 36 kN |
| Basic static load rating C0 | 31.5 kN |
| Mass | 585 g |
| Manufacturer designation | NSK 6918VV |
| Standard | ISO 15 |
| Catalog version | NSK Rolling Bearings E1103 Part C |
| Last verified | 2026-09-24 |
Source: catalog reference (NSK Rolling Bearings E1103 Part C) · extracted 2026-09-24
Dimensions in inches & 61900-series range
| Bore d | 3.543 in |
|---|---|
| Outer diameter D | 4.921 in |
| Width B | 0.709 in |
| ISO bore code | 18 |
| Radial section height (D−d)/2 | 17.5 mm |
| Smallest bore in 61900-series | 10 mm |
| Largest outer diameter in 61900-series | 420 mm |
| Width range across 61900-series | 6–56 mm |
| Bore position in 61900-series (smallest first) | 19 of 37 |
| Bore above smallest 61900-series size | 80 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| 61918 | ISO-INTERCHANGE | verify Commonly quoted cross reference; confirm against the target catalog before ordering. | ISO 15 envelope interchange; NSK suffix 6918VV maps to industry-neutral RSR. Verify seal design, grease and speed rating per brand catalogue. |
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 61918-RSR model number is decoded
In the 61900-series (ISO 15 diameter series 9) the last two digits encode the bore: 61918 carries bore code 18 = 90 mm. Outside diameter 125 mm and width 18 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 90 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
- 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
- Mount this 90 mm bore bearing by heating the inner ring (induction heater, max 120 °C) — never drive it home through the outer ring or balls, that brinells the raceways.
- The 619xx thin section (17.5 mm section height at 90 mm bore) trades load capacity for compactness; stiff, accurately aligned seats are essential or edge loading will spall the raceway early.
- RSR low-friction seals on 61918-RSR run faster than contact-seal 61918-2RS but let fine dust and moisture past the non-contact lip; in dirty or wet duty specify 61918-2RS instead.
- The non-contact lip of 61918-RSR does not retain a lifetime grease fill the way a contact seal does; confirm the regreasing interval for the 90 mm bore position before relying on it as sealed-for-life.
- A 90 mm bore listing showing the right d/D/B but no standard or precision-class reference may be a loose-tolerance import; measure bore/OD spread before fitting it to a machined shaft.
- NSK catalogues this low-friction non-contact seal as 6918VV (suffix VV), the NSK equivalent of the industry-neutral -RSR spelling on this page. VV is not liquid-tight; NSK's contact-seal suffix DDU (industry-neutral -2RS) is the choice for wet or fine-dust duty.
- The 36/31.5 kN ratings, mass 585 g here are NSK Rolling Bearings E1103 Part C catalogue figures for 6918VV; this seal/size combination has no counterpart in the SKF 17000 extract used elsewhere on this site, so the page rests on a single manufacturer source — internal geometry and ratings legitimately differ between brands, so re-verify before substituting in a rated drive.
Frequently asked questions
What are the dimensions of a 61918-RSR bearing?
A 61918-RSR deep-groove ball bearing has a 90 mm bore, 125 mm outer diameter and 18 mm width (3.543 × 4.921 × 0.709 in), per ISO 15 boundary dimensions. It is fitted with two low-friction non-contact rubber seals.
How does the 61918 bore code work?
The last two digits of 61918 are bore code 18, giving 18 × 5 = 90 mm bore. The 125 mm outside diameter and 18 mm width follow the ISO 15 diameter series, not the bore code alone.
What does the RSR suffix on 61918-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 61900 compare with other series at the same 90 mm bore?
619 is a thin section one step above 618: 125×18 mm with a 17.5 mm radial section at 90 mm bore; a 6218 on the same bore is substantially larger and more heavily rated.
What is the NSK designation and catalogue data for 61918-RSR?
In the NSK Rolling Bearings catalogue (E1103 Part C) this size is listed as 6918VV — two low-friction non-contact rubber seals (NSK suffix VV), 90×125×18 mm per ISO 15. Quoted values: C 36 kN, C0 31.5 kN, mass 585 g. The industry-neutral page spelling 61918-RSR follows the seal-suffix convention used across this site, not NSK order-number spelling. Reference and limiting speeds are not tabulated in the E1103 dimension tables used here; consult NSK speed tables before high-speed service.
Reviewed & verified by the MPN Base engineering desk against source catalog NSK Rolling Bearings E1103 Part C on 2026-09-24. Read our editorial & correction policy.