6221-RSR 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 6221-RSR model number is decoded

6221-RSR uses two non-contact elastomer lips with very low drag; coarse debris stays out, but the bearing is not liquid-tight. Within the light 62xx section (diameter series 2 of ISO 15), multiplying bore code 21 by five gives the 105 mm bore; the 190 mm outside diameter and 36 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 6221VV), 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

• Mount this 105 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 62xx light series is the default general-purpose section at 105 mm bore; before upgrading to a 6321 for extra capacity, confirm the housing accepts a 190 mm OD and 36 mm width — it is not a drop-in swap.
• The low-drag lip of 6221-RSR barely touches the inner ring; after long shelf storage the grease can separate, so rotate the rings by hand and confirm smooth, silent running before fitting.
• The non-contact lip of 6221-RSR 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.
• Assign fits by which ring rotates: an interference shaft fit for a rotating inner ring; if the outer ring rotates instead, reverse the logic — a loose rotating ring creeps and frets its seat.
• Deep-groove ball bearings tolerate only minutes of misalignment; if the 190 mm housing cannot be aligned, switch to a self-aligning type rather than shimming 6221-RSR.
• NSK catalogues this low-friction non-contact seal as 6221VV (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 6221 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.
• NSK rates 6221 at 146 kN dynamic (C) and 105 kN static (C0); this heavy-load rating is at the upper end of the E1103 Part C single-row deep-groove extract — NSK supplies a machined brass cage (suffix M) and expects an application review, because catalogue L10 life alone does not capture shock and misalignment loads at this rating.
• At 3790 g (3.8 kg), 6221 needs mechanical handling for mounting; NSK recommends induction heating the inner ring (max 120 °C) rather than pressing cold, and a lifting eye if the housing is pre-assembled.
• The 105×190×36 mm envelope of 6221 gives a D/d ratio of 1.81 and 42.5 mm radial section height — a standard NSK medium section that balances load capacity and speed; for this geometry the pressed-steel cage is adequate up to NSK's listed speed ratings, and C3 clearance is the common choice for hot shafts.
• The 146/105 kN load ratings, mass 3790 g here are NSK Rolling Bearings E1103 Part C catalogue figures for 6221VV on the 105×190×36 mm ISO 15 envelope; internal geometry and ratings legitimately differ between brands, so re-verify before substituting another manufacturer's 6221 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.
• When replacing a failed unit, inspect the shaft and housing seats before fitting the new 6221 — a new bearing pressed onto a worn or oval seat reproduces the original failure mode in a fraction of its expected life.
• NSK supplies its sealed units pre-greased for general duty between roughly -10 and +110 °C; low-temperature, food-grade and high-temperature fills are special executions — ask at order time, because DDU/VV units are not designed to be opened and repacked.