6309-ZZ-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 6309-ZZ-NTN model number is decoded

6309-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 09 by five gives the 45 mm bore; the 100 mm outside diameter and 25 mm width follow the same boundary-dimension plan. For a rotating inner ring on a 45 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 catalogue order number: 6309ZZ (suffix ZZ), two non-contact steel shields, mapped here from the industry-neutral -ZZ spelling.

Typical equipment & failure modes

Selection pitfalls — read before you substitute

• A 45 mm shaft for 6309 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 45 mm bore through a 100 mm OD and 25 mm width; the heavier rolling elements also trade away some speed versus a 6209.
• Do not wash 6309-ZZ-NTN 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 6309-ZZ-NTN units are typically greased for life; prying the shields out for regreasing usually bends them and leaves a gap that throws grease in service.
• Suffixes stack in a defined order — clearance follows the seal code, e.g. 6309-ZZ-NTN-C3. No clearance suffix means normal CN clearance.
• Vibration during standstill brinells the raceways of a 45 mm bearing at ball spacing; if the machine sits idle next to running equipment, turn the shaft over periodically or isolate the arrangement.
• NTN catalogues the shielded version as 6309ZZ — suffix ZZ, two non-contact steel shields. The industry-neutral page spelling is -ZZ; quote the NTN order number when buying through an NTN channel.
• The 45 mm bore puts 6309 in NTN's general-purpose industrial range; the standard pressed-steel cage and CN clearance cover most electric-motor and 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 5600 r/min the grease limiting speed for 6309 covers medium-duty industrial drives; the open or shielded execution can run continuously at this speed with standard lithium-soap grease.
• NTN rates 6309 at 58.5 kN dynamic (C) and 32 kN static (C0), 2.5 kN fatigue load limit Cu; this upper-medium rating covers conveyor and gearbox drives, but at these loads the pressed-steel cage can be the limiting factor under shock — consider the machined brass cage (suffix M) for impact duty.
• At 814 g, 6309 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 45×100×25 mm envelope of 6309 gives a D/d ratio of 2.22 and 27.5 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 58.5/32 kN load ratings, 2.5 kN fatigue load limit Cu NTN lists the grease limiting speed at 5600 r/min for this designation; oil-mist or jet lubrication raises the ceiling but requires a sealed-housing review. and 814 g mass here are NTN Ball and Roller Bearings CAT.No.2203-3/E figures for 6309ZZ on the 45×100×25 mm ISO 15 envelope; internal geometry and ratings legitimately differ between brands, so re-verify before substituting another manufacturer's 6309 in a rated drive.
• Order the C3 internal-clearance version (6309 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.
• NTN date-codes its packaging; rotate stock first-in-first-out, because the grease inside sealed units ages on the shelf — after three to five years of storage, check the grease condition before putting the bearing into service.