6305-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 6305-ZZ-FAG model number is decoded

6305-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 medium 63xx section (diameter series 3 of ISO 15), multiplying bore code 05 by five gives the 25 mm bore; the 62 mm outside diameter and 17 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: 6305-C-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

• A 25 mm shaft for 6305 should be finished to Ra ≤ 1.6 µm with square seating faces; at this bore a scored or oval journal shows up directly as running noise and early raceway damage.
• The 63xx medium series gains rating at 25 mm bore through a 62 mm OD and 17 mm width; the heavier rolling elements also trade away some speed versus a 6205.
• ZZ shields are non-contact: 6305-ZZ-FAG blocks chips and coarse dust but is not waterproof — do not install it expecting a pressure-wash seal, step up to 6305-2RS for that.
• Shielded 6305-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 17 mm-wide ring seats square; provide an undercut or withdrawal groove instead of relying on an oversized radius.
• Measure the shaft, do not trust the drawing: a 25 mm nominal journal worn by even 0.02 mm turns an interference seat into a creeping fit that frets the bore of 6305-ZZ-FAG.
• Schaeffler HR 1 lists the shielded version as 6305-C-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 6305 at 15100 r/min mechanical limiting speed (thermal reference speed 13500 r/min) — electric-motor territory; prefer the open or 2Z execution (sealed 2RSR variants lose roughly a third of the thermal speed) and confirm grease life at the reference speed for continuous running.
• The 25 mm bore puts 6305 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 26.5 kN dynamic load rating (C) and 11.5 kN static (C0), 6305 is a medium-load FAG bearing for most electric-motor and pump duty; check the static safety factor against C0 for preloaded or thrust-loaded arrangements.
• At 224 g, 6305 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 25×62×17 mm envelope of 6305 gives a D/d ratio of 2.48 and 18.5 mm radial section height — a heavy FAG section for high-load, lower-speed duty; specifying it in a high-rpm motor generates excess heat and shortens grease life, so prefer a 62/63-series there.
• The 26.5/11.5 kN load ratings, mass 224 g here are Schaeffler HR 1 Rolling Bearings (Jan 2020) catalogue figures for 6305-C-2Z on the 25×62×17 mm ISO 15 envelope; internal geometry and ratings legitimately differ between brands, so re-verify before substituting another manufacturer's 6305 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 has moved many HR 1 sizes to the X-life generation with higher C/C0 ratings; the designation is unchanged, so a current eKatalog listing for 6305 may quote higher values than the HR 1 print figures on this page — the envelope is identical either way.
• 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.