6406-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 6406-NTN model number is decoded

6406 is supplied open, without shields or seals, so the arrangement around it must supply and retain the lubricant. Within the heavy 64xx section (diameter series 4 of ISO 15), multiplying bore code 06 by five gives the 30 mm bore; the 90 mm outside diameter and 23 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 NTN catalogue this open execution carries the bare designation; protected variants are ordered separately with suffixes ZZ (shields), LLB/LLF (non-contact seals), LLH (low-torque contact seal) and LLU (contact seal).

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 6406-NTN; check shaft finish and runout (target Ra ≤ 1.6 µm) before pressing it home.
• The 64xx heavy section at 30 mm bore exists for high radial load at moderate rpm; its 90 mm OD and 23 mm width demand a larger housing, and grease life at motor speeds is short — treat it as a low-speed, high-load choice.
• Storage matters for open bearings: 6406-NTN 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.
• Open bearings tolerate the highest speeds in the 6400-series but need a defined regreasing interval; run-to-failure lubrication is the dominant cause of early failure in open 6406 units.
• Grease compatibility is not guaranteed between fills: mixing lithium and polyurea thickeners in a 6400-series position can soften the mixture and leak — clean out the old fill before switching grease types.
• Shaft and housing fillets must clear the bearing chamfer so the 23 mm-wide ring seats square; provide an undercut or withdrawal groove instead of relying on an oversized radius.
• The open 6406 has no integral sealing; in the NTN 2203 catalogue the protected variants carry suffixes ZZ (non-contact steel shields), LLB/LLF (non-contact rubber seals), LLU (contact rubber seals) and LLH (a low-torque contact seal with higher speed capability than LLU). A JR or JRX suffix (printed for some thin-section sizes) denotes a pressed-steel cage, not a seal.
• The 30 mm bore puts 6406 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 8800 r/min the grease limiting speed for 6406 covers most general-purpose industrial drives; the open or shielded execution can run continuously at this speed with standard lithium-soap grease.
• NTN rates 6406 at 48 kN dynamic (C) and 23.9 kN static (C0), 1.86 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 735 g, 6406 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 30×90×23 mm envelope of 6406 gives a D/d ratio of 3.00 and 30.0 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 48/23.9 kN load ratings, 1.86 kN fatigue load limit Cu NTN lists the grease limiting speed at 8800 r/min for this designation; oil-mist or jet lubrication raises the ceiling but requires a sealed-housing review. and 735 g mass here are NTN Ball and Roller Bearings CAT.No.2203-3/E figures for 6406 on the 30×90×23 mm ISO 15 envelope; internal geometry and ratings legitimately differ between brands, so re-verify before substituting another manufacturer's 6406 in a rated drive.
• Order the C3 internal-clearance version (6406 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's pressed-steel cage (no cage suffix) is the quiet standard for this size; for sustained running close to the limiting speed or for heavy shock duty, ask the NTN channel whether a machined-cage execution of 6406 is listed.