EZO R4ZZ dimensions and model reference
EZO R4ZZ is listed as a inch-series ball bearing with a 6.35 mm bore, 15.875 mm body outside diameter and 4.978 mm inner-ring width B. Its outer-ring width C is 4.978 mm.
Basic dynamic radial rating Cr: 1.48 kN; basic static radial rating C0r: 0.617 kN. Reference mass: 4.19 g.
How to compare this exact model
- The shorthand 6.35×15.875×4.978 mm uses d×D×B. Keep C separately when comparing ring seating or axial envelopes; B and C are not interchangeable labels.
- The exact catalogue marking identifies two pressed-steel shields. Material interpretation: high-carbon chromium bearing steel. These interpretations use EZO’s code system, not a universal cross-brand suffix rule.
- The original metric and inch entries are both retained as published. Their rounding may differ from a calculation using extra decimal places; do not treat the displayed decimals as a tolerance.
- Cr and C0r are radial rating inputs, not a universal safe working load. An application still needs its actual load, speed, life, mounting and lubrication conditions checked.
- Grease and oil limits are shown separately. They are catalogue reference conditions, not a guaranteed operating speed for every seal, cage, temperature, cooling arrangement or rotating ring.
- The table does not establish your ordered precision class, internal clearance, grease fill or cage option. An ABEC grade or C3 clearance must not be supplied from a nearby model.
- Equal dimensions do not certify machine, bicycle, vehicle or other equipment fitment. Keep the complete brand and suffix when comparing candidates.
Source basis:Kitanihon Seiki / EZO public model specification, catalogue record 01501; collected 2026-10-02. Closure and material explanations use its numbering guide. BearingScope reorganises factual attributes for independent lookup; this is not a manufacturer drawing or replacement approval.
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