6221-2RS-NTN bearing: complete specifications & equivalents

Specification table

Source: catalog reference (NTN Ball and Roller Bearings CAT.No.2203-3/E (2024)) · extracted 2026-09-25

Parameters extracted from the official NTN Ball and Roller Bearings catalogue (NTN Ball and Roller Bearings CAT.No.2203-3/E (2024)); NTN® is a trademark of NTN Corporation, used here for identification only — mpnbase is not an authorized NTN distributor. Boundary dimensions are ISO 15 interchangeable; current production values may differ, verify at ntnglobal.com.

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 6221-2RS-NTN model number is decoded

In the 6200-series (diameter series 2 of ISO 15) the last two digits encode the bore: 6221 carries bore code 21 = 105 mm. Outside diameter 190 mm and width 36 mm come from the ISO 15 boundary-dimensions general plan. Suffix -2RS denotes two contact-type elastomer seals over a lifetime grease fill; the sealing lips add drag compared with open or shielded versions. For normal-load mounting with a rotating inner ring on a 105 mm shaft, typical catalogue practice is a m6 shaft seat with an H7 housing bore — verify against the actual load direction and magnitude. NTN's contact-seal catalogue number is 6221LLU (suffix LLU, or LLH low-torque variant), mapped here from the industry-neutral -2RS spelling; the contacting lip lowers the speed ceiling versus the open bearing.

Typical equipment & failure modes

Selection pitfalls — read before you substitute

• Large bores like the 105 mm of 6221-2RS-NTN 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 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.
• Contact seals add drag and heat: 6221-2RS-NTN runs slower and cooler-limited than the open 6221; rubber lips are generally limited to roughly 80–110 °C continuous depending on grease, and C3 clearance is the common hot-duty choice.
• Never wash a sealed 6221-2RS-NTN in solvent or press it home via the outer ring; solvent destroys the grease thickener and mounting force through the seal deforms the lip.
• 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 6221-2RS-NTN.
• Measure the shaft, do not trust the drawing: a 105 mm nominal journal worn by even 0.02 mm turns an interference seat into a creeping fit that frets the bore of 6221-2RS-NTN.
• NTN catalogues the contact-sealed version as 6221LLU (suffix LLU), mapped here from the industry-neutral -2RS spelling; it is greased for life and the contacting lip lowers the speed ceiling versus the open bearing.
• At 105 mm bore 6221 is in NTN's medium industrial range; the pressed-steel cage is standard but large-section 63xx/64xx 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 NTN channel if the application sees impact loads.
• NTN lists the grease limiting speed at 2300 r/min for 6221; this is a large or heavy-section size where centrifugal force and cage inertia cap the speed — for higher shaft speeds either step to a smaller bearing on the same bore or consult NTN for an oil-lubricated, machined-cage variant.
• At 147 kN dynamic load rating (C) and 105 kN static (C0), 6.75 kN fatigue load limit Cu, 6221 is a heavy-load bearing for industrial gearboxes and large conveyors; NTN expects a machined brass cage (suffix M) at this rating for shock duty, and the static C0 must be checked against any mounting or lifting loads.
• At 3700 g (3.7 kg), 6221 needs mechanical handling for mounting; NTN 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 medium section that balances load capacity and speed; for this geometry the pressed-steel cage is adequate up to the listed limiting speed, and C3 clearance is the common choice for hot shafts.
• The 147/105 kN load ratings, 6.75 kN fatigue load limit Cu NTN lists the grease limiting speed at 2300 r/min for this designation; oil-mist or jet lubrication raises the ceiling but requires a sealed-housing review. and 3700 g mass here are NTN Ball and Roller Bearings CAT.No.2203-3/E figures for 6221LLU 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.
• Two NTN bearings of the same designation from different production lots can carry minor internal-geometry revisions; for paired or preloaded arrangements on one shaft, order a single lot through the NTN distributor.
• Order the C3 internal-clearance version (6221 with C3 after the seal code) when the shaft fit is tight or the shaft-to-housing temperature gradient exceeds roughly 10 °C — the residual clearance after mounting, not the catalogue CN figure, decides service life.