61821-RSR-NSK bearing: complete specifications & equivalents

Specification table

Source: catalog reference (NSK Rolling Bearings E1103 Part C) · extracted 2026-09-24

Cross references & equivalents

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 61821-RSR-NSK model number is decoded

61821-RSR uses two non-contact elastomer lips with very low drag; coarse debris stays out, but the bearing is not liquid-tight. Within the extra-thin 618xx section (diameter series 8 of ISO 15), multiplying bore code 21 by five gives the 105 mm bore; the 130 mm outside diameter and 13 mm width follow the same boundary-dimension plan. For a rotating inner ring on a 105 mm shaft under normal load, catalogue practice seats it on a m6 shaft fit with an H7 housing bore — confirm against the actual load direction and magnitude before committing. NSK's non-contact seal suffix is VV (catalogue number 6821VV), mapped here from the industry-neutral -RSR spelling; speed capability is close to the open bearing but VV is not liquid-tight.

Typical equipment & failure modes

Selection pitfalls — read before you substitute

• Large bores like the 105 mm of 61821-RSR-NSK demand clean, burr-free seats; one raised burr under a ring this size cocks the bearing and concentrates load at the raceway edge, cutting life drastically.
• The 618xx thin section at 105 mm bore has only a 12.5 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 6221.
• RSR low-friction seals on 61821-RSR-NSK run faster than contact-seal 61821-2RS but let fine dust and moisture past the non-contact lip; in dirty or wet duty specify 61821-2RS instead.
• The non-contact lip of 61821-RSR-NSK does not retain a lifetime grease fill the way a contact seal does; confirm the regreasing interval for the 105 mm bore position before relying on it as sealed-for-life.
• Axial location must clamp the ring face, not the seal area: a shoulder or circlip bearing on the seal side of the 13 mm-wide ring of 61821-RSR-NSK drags the lip and overheats it.
• Shaft and housing fillets must clear the bearing chamfer so the 13 mm-wide ring seats square; provide an undercut or withdrawal groove instead of relying on an oversized radius.
• NSK catalogues this low-friction non-contact seal as 6821VV (suffix VV), mapped here from the industry-neutral -RSR spelling. NSK rates its speed capability close to the open bearing, but VV is not liquid-tight — for wet or fine-dust duty step up to the DDU contact seal (industry-neutral -2RS).
• At 105 mm bore 61821 is in NSK's medium industrial range; the pressed-steel cage is standard, but large-section 63xx sizes at this bore can be ordered with a machined brass cage (suffix M) for heavy-shock or very-low-speed duty — confirm cage material with the NSK channel if the application sees impact loads.
• At 21.8 kN dynamic load rating (C) and 23.9 kN static (C0), 61821 is a medium-load NSK bearing suitable for most electric-motor and pump duty; the C0/C0r ratio matters for preloaded or thrust-loaded arrangements, so confirm the static safety factor with the NSK catalogue.
• At 324 g, 61821 requires a soft-jaw vise or arbor press for mounting — never hammer it onto the shaft, and support the opposite ring to avoid brinelling the raceways.
• The 105×130×13 mm envelope of 61821 gives a D/d ratio of 1.24 and only 12.5 mm radial section height — this is an ultra-thin section in NSK's E1103 catalogue where shaft deflection and housing ovality directly load the ball-raceway contact; verify shaft stiffness (target deflection under 0.05 mm) before specifying it over a 62-series.
• The 21.8/23.9 kN load ratings, mass 324 g here are NSK Rolling Bearings E1103 Part C catalogue figures for 6821VV on the 105×130×13 mm ISO 15 envelope; internal geometry and ratings legitimately differ between brands, so re-verify before substituting another manufacturer's 61821 in a rated drive. NSK does not tabulate reference or limiting speeds in the E1103 Part C dimension tables used for this page — consult NSK's separate speed-rating tables before high-speed service.
• NSK does not recommend washing new shielded or sealed bearings; the rust-preventive film on open units is compatible with standard lithium greases and needs no removal unless the application demands a special fill.
• NSK's VV non-contact seal keeps frictional torque close to the open 61821; in motor duty where heat build-up matters, VV is the usual compromise between debris protection and speed capability.