6306-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-FAG model number is decoded

6306 is supplied open, without shields or seals, so the arrangement around it must supply and retain the lubricant. 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. In the Schaeffler HR 1 catalogue this open execution carries the bare designation; protected variants are ordered separately with suffixes 2Z (steel shields), 2RZ (non-contact rubber seals) and 2RSR (lip-contact rubber seals).

Typical equipment & failure modes

Selection pitfalls — read before you substitute

• Sizes around 30 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 6306-FAG.
• 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.
• The open 6306-FAG has no lubricant retention: grease escapes and contaminants migrate straight into the 30×72×19 mm raceway, so specify a sealed arrangement for dusty or washdown duty.
• Storage matters for open bearings: 6306-FAG leaves the factory with rust preventive only, so clean it and apply the service grease at assembly even if the rings look oily from the wrapper.
• Shaft and housing fillets must clear the bearing chamfer so the 19 mm-wide ring seats square; provide an undercut or withdrawal groove instead of relying on an oversized radius.
• Grease compatibility is not guaranteed between fills: mixing lithium and polyurea thickeners in a 6300-series position can soften the mixture and leak — clean out the old fill before switching grease types.
• The open 6306 has no integral sealing; in the Schaeffler HR 1 catalogue the protected variants carry suffixes 2Z (two steel shields), 2RZ (two non-contact rubber seals) and 2RSR (two lip-contact rubber seals). Do not confuse FAG's 2RZ with a contact seal — the RZ lip does not touch the inner ring, which is why its speed capability stays close to the open bearing.
• FAG rates 6306 at 15100 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 328 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 328 g here are Schaeffler HR 1 Rolling Bearings (Jan 2020) catalogue figures for 6306-C 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.
• 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 6306 may quote higher values than the HR 1 print figures on this page — the envelope is identical either way.
• FAG standard tolerance for this size is P0 (PN); P6/P5 precision executions exist for spindle-adjacent duty but carry different order numbers in the Schaeffler system — they are not a selectable sorting of standard stock.