61810-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 61810-RSR-NTN model number is decoded

61810-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 10 by five gives the 50 mm bore; the 65 mm outside diameter and 7 mm width follow the same boundary-dimension plan. For a rotating inner ring on a 50 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 6810JRLLB), 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

• Temperature rise and interference fits consume internal clearance on this 50 mm bore: a CN bearing on a tight, hot shaft can lose all residual clearance — size 61810 with C3 for those conditions.
• Only 7.5 mm of radial section separates bore and OD on the 618xx series at 50 mm: ring flex from clamping or an oval housing bore transfers straight into raceway stress, so seat roundness matters more here than on a 6210.
• The low-drag lip of 61810-RSR-NTN 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 61810-RSR-NTN does not retain a lifetime grease fill the way a contact seal does; confirm the regreasing interval for the 50 mm bore position before relying on it as sealed-for-life.
• Do not quieten a noisy bearing by preloading it: the 61800-series is a deep-groove design, not angular-contact; axial preload raises temperature and shortens grease 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.
• NTN catalogues this low-friction non-contact seal as 6810JRLLB (suffix RLLB), 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).
• The 50 mm bore puts 61810 in NTN's general-purpose industrial range; the standard pressed-steel cage and CN clearance cover most electric-motor and pump duty, but for continuous high-speed use specify the LLH low-torque seal (not LLU) and confirm the housing allows the listed limiting speed.
• At 9600 r/min the grease limiting speed for 61810 covers most general-purpose industrial drives; the open or shielded execution can run continuously at this speed with standard lithium-soap grease.
• NTN rates 61810 at 7.3 kN dynamic (C) and 6.1 kN static (C0), 0.41 kN fatigue load limit Cu; this light-to-medium rating suits fractional-horsepower drives and instruments — for conveying or gearbox duty with shock loads, verify the equivalent dynamic load stays well below C.
• At 52 g, 61810 is light enough for hand assembly but should be pressed on with a fitting sleeve against the inner ring; do not strike the outer ring or cage with a hammer.
• The 50×65×7 mm envelope of 61810 gives a D/d ratio of 1.30 and only 7.5 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 7.3/6.1 kN load ratings, 0.41 kN fatigue load limit Cu NTN lists the grease limiting speed at 9600 r/min for this designation; oil-mist or jet lubrication raises the ceiling but requires a sealed-housing review. and 52 g mass here are NTN Ball and Roller Bearings CAT.No.2203-3/E figures for 6810JRLLB on the 50×65×7 mm ISO 15 envelope; internal geometry and ratings legitimately differ between brands, so re-verify before substituting another manufacturer's 61810 in a rated drive.
• Standard catalogue stock of 61810 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.
• NTN date-codes its packaging; rotate stock first-in-first-out, because the grease inside sealed units ages on the shelf — after three to five years of storage, check the grease condition before putting the bearing into service.