61820-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 61820-NTN model number is decoded

In the 61800-series (diameter series 8 of ISO 15) the last two digits encode the bore: 61820 carries bore code 20 = 100 mm. Outside diameter 125 mm and width 13 mm come from the ISO 15 boundary-dimensions general plan. With no seal suffix the bearing is open: no shields or seals are fitted and lubrication is supplied by the application. For normal-load mounting with a rotating inner ring on a 100 mm shaft, typical catalogue practice is a k5 shaft seat with an H7 housing bore — verify against the actual load direction and magnitude. In the NTN catalogue this open execution carries the bare designation; protected variants are ordered separately with suffixes ZZ (shields), LLB/LLF (non-contact seals), LLH (low-torque contact seal) and LLU (contact seal).

Typical equipment & failure modes

Selection pitfalls — read before you substitute

• Mount this 100 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.
• Only 12.5 mm of radial section separates bore and OD on the 618xx series at 100 mm: ring flex from clamping or an oval housing bore transfers straight into raceway stress, so seat roundness matters more here than on a 6220.
• The open 61820-NTN has no lubricant retention: grease escapes and contaminants migrate straight into the 100×125×13 mm raceway, so specify a sealed arrangement for dusty or washdown duty.
• Open bearings tolerate the highest speeds in the 61800-series but need a defined regreasing interval; run-to-failure lubrication is the dominant cause of early failure in open 61820 units.
• Never mix components between two 61820-NTN units: rings, cage and balls are factory-matched and are not field-interchangeable, even between identical designations.
• Vibration during standstill brinells the raceways of a 100 mm bearing at ball spacing; if the machine sits idle next to running equipment, turn the shaft over periodically or isolate the arrangement.
• The open 61820 has no integral sealing; in the NTN 2203 catalogue the protected variants carry suffixes ZZ (non-contact steel shields), LLB/LLF (non-contact rubber seals), LLU (contact rubber seals) and LLH (a low-torque contact seal with higher speed capability than LLU). A JR or JRX suffix (printed for some thin-section sizes) denotes a pressed-steel cage, not a seal.
• At 100 mm bore 61820 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 4800 r/min for 61820; 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 21.7 kN dynamic load rating (C) and 21.2 kN static (C0), 1.33 kN fatigue load limit Cu, 61820 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 313 g, 61820 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 100×125×13 mm envelope of 61820 gives a D/d ratio of 1.25 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 21.7/21.2 kN load ratings, 1.33 kN fatigue load limit Cu NTN lists the grease limiting speed at 4800 r/min for this designation; oil-mist or jet lubrication raises the ceiling but requires a sealed-housing review. and 313 g mass here are NTN Ball and Roller Bearings CAT.No.2203-3/E figures for 6820 on the 100×125×13 mm ISO 15 envelope; internal geometry and ratings legitimately differ between brands, so re-verify before substituting another manufacturer's 61820 in a rated drive.
• Factory-fill grease in NTN sealed units is a general-duty lithium-soap grease; food-grade, low-temperature and high-temperature fills are request options at order time, because LLU/LLB units are not meant to be opened and re-greased in the field.
• Standard catalogue stock of 61820 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.