61809-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 61809-NTN model number is decoded

61809 is supplied open, without shields or seals, so the arrangement around it must supply and retain the lubricant. Within the extra-thin 618xx section (diameter series 8 of ISO 15), multiplying bore code 09 by five gives the 45 mm bore; the 58 mm outside diameter and 7 mm width follow the same boundary-dimension plan. For a rotating inner ring on a 45 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. 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

• At a 45 mm bore, a shaft-seat burr or an overtight setscrew can score the thin inner ring of 61809-NTN; check shaft finish and runout (target Ra ≤ 1.6 µm) before pressing it home.
• Only 6.5 mm of radial section separates bore and OD on the 618xx series at 45 mm: ring flex from clamping or an oval housing bore transfers straight into raceway stress, so seat roundness matters more here than on a 6209.
• The open 61809-NTN has no lubricant retention: grease escapes and contaminants migrate straight into the 45×58×7 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 61809 units.
• 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.
• A 45 mm bore listing showing the right d/D/B but no standard or precision-class reference may be a loose-tolerance import; measure bore/OD spread before fitting it to a machined shaft.
• The open 61809 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.
• The 45 mm bore puts 61809 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 11000 r/min the grease limiting speed for 61809 covers most general-purpose industrial drives; the open or shielded execution can run continuously at this speed with standard lithium-soap grease.
• NTN rates 61809 at 5.95 kN dynamic (C) and 4.95 kN static (C0), 0.33 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 only 40 g, 61809 is a lightweight bearing that can be handled by hand; still, press it onto the shaft with a sleeve against the inner ring — never through the balls or outer ring.
• The 45×58×7 mm envelope of 61809 gives a D/d ratio of 1.29 and only 6.5 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 5.95/4.95 kN load ratings, 0.33 kN fatigue load limit Cu NTN lists the grease limiting speed at 11000 r/min for this designation; oil-mist or jet lubrication raises the ceiling but requires a sealed-housing review. and 40 g mass here are NTN Ball and Roller Bearings CAT.No.2203-3/E figures for 6809JR on the 45×58×7 mm ISO 15 envelope; internal geometry and ratings legitimately differ between brands, so re-verify before substituting another manufacturer's 61809 in a rated drive.
• Standard catalogue stock of 61809 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's pressed-steel cage (no cage suffix) is the quiet standard for this size; for sustained running close to the limiting speed or for heavy shock duty, ask the NTN channel whether a machined-cage execution of 61809 is listed.