6306-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 6306-ZZ-FAG model number is decoded

6306-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 06 by five gives the 30 mm bore; the 72 mm outside diameter and 19 mm width follow the same boundary-dimension plan. For a rotating inner ring on a 30 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: 6306-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

• At a 30 mm bore, a shaft-seat burr or an overtight setscrew can score the thin inner ring of 6306-ZZ-FAG; check shaft finish and runout (target Ra ≤ 1.6 µm) before pressing it home.
• The 63xx medium section at 30 mm bore gains dynamic rating through larger rolling elements on a 72 mm OD; the penalty is mass and a lower limiting speed than the 6206 — do not specify it for speed-critical shafts.
• Do not wash 6306-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 6306-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.
• Axial location must clamp the ring face, not the seal area: a shoulder or circlip bearing on the seal side of the 19 mm-wide ring of 6306-ZZ-FAG drags the lip and overheats it.
• A 30 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.
• Schaeffler HR 1 lists the shielded version as 6306-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 6306 at 12800 r/min mechanical limiting speed (thermal reference speed 11500 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 30 mm bore puts 6306 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 32 kN dynamic load rating (C) and 16.2 kN static (C0), 6306 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 345 g, 6306 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 30×72×19 mm envelope of 6306 gives a D/d ratio of 2.40 and 21.0 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 32/16.2 kN load ratings, mass 345 g here are Schaeffler HR 1 Rolling Bearings (Jan 2020) catalogue figures for 6306-C-2Z on the 30×72×19 mm ISO 15 envelope; internal geometry and ratings legitimately differ between brands, so re-verify before substituting another manufacturer's 6306 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.
• FAG sealed units arrive greased for life with a lithium-soap fill; Schaeffler quotes a shelf life for greased bearings and recommends running stock first-in-first-out rather than re-greasing aged sealed units.
• Schaeffler's medias/eKatalog is the live source for the current execution of 6306: cage material, seal lip design and ratings can be revised between catalogue generations without any designation change.