61805-ZZ-FAG bearing: complete specifications & equivalents

Specification table

Source: catalog reference (HR 1 Rolling Bearings (Jan 2020)) · extracted 2026-09-25

Parameters extracted from the official FAG Rolling Bearings catalogue (HR 1 Rolling Bearings (Jan 2020)); FAG® is a trademark of Schaeffler Technologies AG & Co. KG, used here for identification only — mpnbase is not an authorized FAG/Schaeffler distributor. Boundary dimensions are ISO 15 interchangeable; current production values may differ, verify at schaeffler.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 61805-ZZ-FAG model number is decoded

61805-ZZ carries two non-contact sheet-steel shields that hold the factory grease in and keep coarse debris out; they do not seal against liquids. Within the extra-thin 618xx section (diameter series 8 of ISO 15), multiplying bore code 05 by five gives the 25 mm bore; the 37 mm outside diameter and 7 mm width follow the same boundary-dimension plan. For a rotating inner ring on a 25 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. Schaeffler HR 1 catalogue order number: 61805-2Z (FAG suffix 2Z), two non-contact steel shields, mapped here from the industry-neutral -ZZ spelling.

Typical equipment & failure modes

Selection pitfalls — read before you substitute

• Sizes around 25 mm bore are normally pressed on cold with a sleeve against the inner-ring face; the press force must never route through the outer ring or the balls of 61805-ZZ-FAG.
• Only 6.0 mm of radial section separates bore and OD on the 618xx series at 25 mm: ring flex from clamping or an oval housing bore transfers straight into raceway stress, so seat roundness matters more here than on a 6205.
• Do not wash 61805-ZZ-FAG in solvent before mounting: the grease inside the shielded cavity is the service fill, and solvent creeping past the shield gap strips it out.
• Shielded 61805-ZZ-FAG units are typically greased for life; prying the shields out for regreasing usually bends them and leaves a gap that throws grease in service.
• Shaft and housing fillets must clear the bearing chamfer so the 7 mm-wide ring seats square; provide an undercut or withdrawal groove instead of relying on an oversized radius.
• Suffixes stack in a defined order — clearance follows the seal code, e.g. 61805-ZZ-FAG-C3. No clearance suffix means normal CN clearance.
• Schaeffler HR 1 lists the shielded version as 61805-2Z — FAG suffix 2Z, two non-contact steel shields. The industry-neutral page spelling is -ZZ; quote the FAG order number when buying through a Schaeffler channel.
• FAG rates 61805 at 24000 r/min mechanical limiting speed (thermal reference speed 13900 r/min) — a high-speed range where the thermal reference speed governs continuous duty; use low-viscosity turbine oil or high-speed grease and avoid lip-contact seals entirely.
• The 25 mm bore puts 61805 in Schaeffler's light industrial range; the standard cage and CN clearance cover most fractional-horsepower motor and small-pump duty, and FAG's X-life generation of these sizes carries higher ratings than legacy HR 1 printings — check the current eKatalog listing before reordering.
• At 4.3 kN dynamic load rating (C) and 2.94 kN static (C0), 61805 is a light-load FAG bearing: L10 life above a few kN of equivalent load is short, so size up to a 62-series on the same bore if the duty sees shock or frequent starts.
• The 25×37×7 mm envelope of 61805 gives a D/d ratio of 1.48 and 6.0 mm radial section height — a thin FAG section that saves space but is sensitive to misalignment and shock; keep the housing round within IT7 and the shaft deflection below the raceway contact envelope.
• The 4.3/2.94 kN load ratings here are Schaeffler HR 1 Rolling Bearings (Jan 2020) catalogue figures for 61805-2Z on the 25×37×7 mm ISO 15 envelope; internal geometry and ratings legitimately differ between brands, so re-verify before substituting another manufacturer's 61805 in a rated drive. Where FAG has since released an X-life version of this size, its expanded C/C0 ratings supersede the HR 1 print values quoted here.
• Schaeffler's medias/eKatalog is the live source for the current execution of 61805: cage material, seal lip design and ratings can be revised between catalogue generations without any designation change.
• Mixing old and new FAG generations of the same designation in one arrangement is dimensionally acceptable, but where ratings matter — preloaded or matched sets — order both positions from the same generation and lot.