Bearings by size

35×80×21 mmbearing

4 standard bearings share the 35×80×21 mm envelope (bore × outside diameter × width). They fit the same shaft and housing bore but are different bearing types.

DesignationTypeLoadsSize
6307Deep groove ball bearingRadial and moderate axial in both directions35 × 80 × 21 mm
1307Self-aligning ball bearingMainly radial; light axial35 × 80 × 21 mm
7307Angular contact ball bearingCombined radial and axial (one direction per bearing)35 × 80 × 21 mm
NU307 / NJ307 / NUP307 / N307Cylindrical roller bearingHigh radial; NJ/NUP limited axial35 × 80 × 21 mm

Same size is not the same bearing. These types carry loads in different directions, have different speed limits and may need different fits, preload or lubrication. Swapping one for another needs an engineering check, not just a matching size.

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