61818-RSR-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 61818-RSR-NTN model number is decoded

61818-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 18 by five gives the 90 mm bore; the 115 mm outside diameter and 13 mm width follow the same boundary-dimension plan. For a rotating inner ring on a 90 mm shaft under normal load, catalogue practice seats it on a k5 shaft fit with an H7 housing bore — confirm against the actual load direction and magnitude before committing. NTN's non-contact seal suffix is LLB/LLF (catalogue number 6818LLB), mapped here from the industry-neutral -RSR spelling; speed capability matches the open bearing but it is not liquid-tight.

Typical equipment & failure modes

Selection pitfalls — read before you substitute

• Large bores like the 90 mm of 61818-RSR-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.
• Only 12.5 mm of radial section separates bore and OD on the 618xx series at 90 mm: ring flex from clamping or an oval housing bore transfers straight into raceway stress, so seat roundness matters more here than on a 6218.
• RSR low-friction seals on 61818-RSR-NTN run faster than contact-seal 61818-2RS but let fine dust and moisture past the non-contact lip; in dirty or wet duty specify 61818-2RS instead.
• The non-contact lip of 61818-RSR-NTN 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.
• 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.
• 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 61818-RSR-NTN drags the lip and overheats it.
• NTN catalogues this low-friction non-contact seal as 6818LLB (suffix LB), mapped here from the industry-neutral -RSR spelling. NTN rates its speed capability the same as the open bearing, but it is not liquid-tight — for wet or fine-dust duty step up to the LLU contact seal (industry-neutral -2RS).
• At 90 mm bore 61818 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.
• At 5400 r/min the grease limiting speed for 61818 covers medium-duty industrial drives; the open or shielded execution can run continuously at this speed with standard lithium-soap grease.
• At 21.1 kN dynamic load rating (C) and 19.7 kN static (C0), 1.3 kN fatigue load limit Cu, 61818 is a medium-load 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 NTN catalogue.
• At 285 g, 61818 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 90×115×13 mm envelope of 61818 gives a D/d ratio of 1.28 and only 12.5 mm radial section height — this is an ultra-thin section 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 21.1/19.7 kN load ratings, 1.3 kN fatigue load limit Cu NTN lists the grease limiting speed at 5400 r/min for this designation; oil-mist or jet lubrication raises the ceiling but requires a sealed-housing review. and 285 g mass here are NTN Ball and Roller Bearings CAT.No.2203-3/E figures for 6818LLB on the 90×115×13 mm ISO 15 envelope; internal geometry and ratings legitimately differ between brands, so re-verify before substituting another manufacturer's 61818 in a rated drive.
• Order the C3 internal-clearance version (61818 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.
• Standard catalogue stock of 61818 is the general-purpose execution; for low-noise motor duty NTN offers low-torque seal and special-grease variants in this size class, which are separate order numbers.