6306-RSR-NSK bearing: complete specifications & equivalents

Specification table

Source: catalog reference (NSK Rolling Bearings E1103 Part C) · extracted 2026-09-24

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-RSR-NSK model number is decoded

6306-RSR uses two non-contact elastomer lips with very low drag; coarse debris stays out, but the bearing is not liquid-tight. 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. NSK's non-contact seal suffix is VV (catalogue number 6306VV), mapped here from the industry-neutral -RSR spelling; speed capability is close to the open bearing but VV is not liquid-tight.

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-RSR-NSK.
• 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.
• RSR low-friction seals on 6306-RSR-NSK run faster than contact-seal 6306-2RS but let fine dust and moisture past the non-contact lip; in dirty or wet duty specify 6306-2RS instead.
• The non-contact lip of 6306-RSR-NSK does not retain a lifetime grease fill the way a contact seal does; confirm the regreasing interval for the 30 mm bore position before relying on it as sealed-for-life.
• 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.
• Never mix components between two 6306-RSR-NSK units: rings, cage and balls are factory-matched and are not field-interchangeable, even between identical designations.
• NSK catalogues this low-friction non-contact seal as 6306VV (suffix VV), mapped here from the industry-neutral -RSR spelling. NSK rates its speed capability close to the open bearing, but VV is not liquid-tight — for wet or fine-dust duty step up to the DDU contact seal (industry-neutral -2RS).
• The 30 mm bore puts 6306 in NSK's light industrial range; the standard pressed-steel cage and CN clearance cover most fractional-horsepower motor and small-pump duty. NSK's VV non-contact seal is the high-speed choice here — DDU contact seal costs roughly 30–40% of the open-bearing speed ceiling.
• At 29.3 kN dynamic load rating (C) and 15 kN static (C0), 6306 is a medium-load NSK bearing suitable for most electric-motor and pump duty; the C0/C0r ratio matters for preloaded or thrust-loaded arrangements, so confirm the static safety factor with the NSK catalogue.
• 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 NSK section built 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 29.3/15 kN load ratings, mass 345 g here are NSK Rolling Bearings E1103 Part C catalogue figures for 6306VV 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. NSK does not tabulate reference or limiting speeds in the E1103 Part C dimension tables used for this page — consult NSK's separate speed-rating tables before high-speed service.
• NSK supplies its sealed units pre-greased for general duty between roughly -10 and +110 °C; low-temperature, food-grade and high-temperature fills are special executions — ask at order time, because DDU/VV units are not designed to be opened and repacked.
• When replacing a failed unit, inspect the shaft and housing seats before fitting the new 6306 — a new bearing pressed onto a worn or oval seat reproduces the original failure mode in a fraction of its expected life.