61906-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 61906-ZZ-NTN model number is decoded

61906-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 thin 619xx section (diameter series 9 of ISO 15), multiplying bore code 06 by five gives the 30 mm bore; the 47 mm outside diameter and 9 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. NTN catalogue order number: 6906ZZ (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

• At a 30 mm bore, a shaft-seat burr or an overtight setscrew can score the thin inner ring of 61906-ZZ-NTN; check shaft finish and runout (target Ra ≤ 1.6 µm) before pressing it home.
• The 619xx thin section (8.5 mm section height at 30 mm bore) trades load capacity for compactness; stiff, accurately aligned seats are essential or edge loading will spall the raceway early.
• ZZ shields are non-contact: 61906-ZZ-NTN blocks chips and coarse dust but is not waterproof — do not install it expecting a pressure-wash seal, step up to 61906-2RS for that.
• Do not wash 61906-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.
• Never mix components between two 61906-ZZ-NTN units: rings, cage and balls are factory-matched and are not field-interchangeable, even between identical designations.
• Measure the shaft, do not trust the drawing: a 30 mm nominal journal worn by even 0.02 mm turns an interference seat into a creeping fit that frets the bore of 61906-ZZ-NTN.
• NTN catalogues the shielded version as 6906ZZ — 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 30 mm bore puts 61906 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 10000 r/min the grease limiting speed for 61906 covers most general-purpose industrial drives; the open or shielded execution can run continuously at this speed with standard lithium-soap grease.
• NTN rates 61906 at 8 kN dynamic (C) and 5 kN static (C0), 0.36 kN fatigue load limit Cu; this light-to-medium rating suits fractional-horsepower drives and instruments — for conveying or gearbox duty with shock loads, verify the equivalent dynamic load stays well below C.
• At only 48 g, 61906 is a lightweight bearing that can be handled by hand; still, press it onto the shaft with a sleeve against the inner ring — never through the balls or outer ring.
• The 30×47×9 mm envelope of 61906 gives a D/d ratio of 1.57 and 8.5 mm radial section height — this thin section saves space but is sensitive to misalignment and shock; confirm the housing stays round within IT7 and the shaft does not deflect past the raceway contact angle under load.
• The 8/5 kN load ratings, 0.36 kN fatigue load limit Cu NTN lists the grease limiting speed at 10000 r/min for this designation; oil-mist or jet lubrication raises the ceiling but requires a sealed-housing review. and 48 g mass here are NTN Ball and Roller Bearings CAT.No.2203-3/E figures for 6906ZZ on the 30×47×9 mm ISO 15 envelope; internal geometry and ratings legitimately differ between brands, so re-verify before substituting another manufacturer's 61906 in a rated drive.
• Order the C3 internal-clearance version (61906 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.
• Standard catalogue stock of 61906 is the general-purpose execution; for low-noise motor duty NTN offers low-torque seal and special-grease variants in this size class, which are separate order numbers.