6305-2RS-NTN bearing: complete specifications & equivalents

Specification table

Source: catalog reference (NTN Ball and Roller Bearings CAT.No.2203-3/E (2024)) · extracted 2026-09-25

Parameters extracted from the official NTN Ball and Roller Bearings catalogue (NTN Ball and Roller Bearings CAT.No.2203-3/E (2024)); NTN® is a trademark of NTN Corporation, used here for identification only — mpnbase is not an authorized NTN distributor. Boundary dimensions are ISO 15 interchangeable; current production values may differ, verify at ntnglobal.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 6305-2RS-NTN model number is decoded

6305-2RS is closed by two contacting elastomer lips over a lifetime grease fill; the lips add friction, so the speed ceiling sits below the open execution. 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. NTN's contact-seal catalogue number is 6305LLU (suffix LLU, or LLH low-torque variant), mapped here from the industry-neutral -2RS spelling; the contacting lip lowers the speed ceiling versus the open bearing.

Typical equipment & failure modes

Selection pitfalls — read before you substitute

• At a 25 mm bore, a shaft-seat burr or an overtight setscrew can score the thin inner ring of 6305-2RS-NTN; check shaft finish and runout (target Ra ≤ 1.6 µm) before pressing it home.
• 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.
• Heat is the enemy of the sealed 6305-2RS: sustained running near the lip temperature limit hardens the rubber, after which grease escapes and dirt tracks in — watch the housing temperature in hot drives.
• Never wash a sealed 6305-2RS-NTN in solvent or press it home via the outer ring; solvent destroys the grease thickener and mounting force through the seal deforms the lip.
• Deep-groove ball bearings tolerate only minutes of misalignment; if the 62 mm housing cannot be aligned, switch to a self-aligning type rather than shimming 6305-2RS-NTN.
• 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 6305-2RS-NTN.
• NTN catalogues the contact-sealed version as 6305LLU (suffix LLU), mapped here from the industry-neutral -2RS spelling; it is greased for life and the contacting lip lowers the speed ceiling versus the open bearing.
• The 25 mm bore puts 6305 in NTN's light industrial range; the standard pressed-steel cage and CN clearance cover most fractional-horsepower motor and small-pump duty, but for continuous high-speed use specify the LLH low-torque seal (not LLU) and confirm the housing allows the listed limiting speed.
• At 8100 r/min the grease limiting speed for 6305 covers most general-purpose industrial drives; the contact seal (LLU) is the main speed limiter here — for continuous operation above 80% of this figure use the open variant with an external labyrinth seal and oil bath.
• At 23.5 kN dynamic load rating (C) and 10.9 kN static (C0), 0.85 kN fatigue load limit Cu, 6305 is a medium-load 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 NTN catalogue.
• At 232 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 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 23.5/10.9 kN load ratings, 0.85 kN fatigue load limit Cu NTN lists the grease limiting speed at 8100 r/min for this designation; oil-mist or jet lubrication raises the ceiling but requires a sealed-housing review. and 232 g mass here are NTN Ball and Roller Bearings CAT.No.2203-3/E figures for 6305LLU 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.
• Order the C3 internal-clearance version (6305 with C3 after the seal code) when the shaft fit is tight or the shaft-to-housing temperature gradient exceeds roughly 10 °C — the residual clearance after mounting, not the catalogue CN figure, decides service life.
• Two NTN bearings of the same designation from different production lots can carry minor internal-geometry revisions; for paired or preloaded arrangements on one shaft, order a single lot through the NTN distributor.