When the bearing number is worn off or the original part is missing, measure the three key dimensions to identify the replacement.
Tools needed
- Digital caliper (recommended) or micrometer
- Clean cloth to wipe the bearing
Three measurements
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Bore (inner diameter, ID) — Measure inside the inner ring. This is the shaft size. Measure in two places and average.
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Outside diameter (OD) — Measure across the outer ring. This is the housing bore size.
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Width (W) — Measure across the side faces. For tapered roller bearings, measure the overall width including both rings.
Common bearing dimension patterns
Deep groove ball bearings follow standard ISO series patterns:
| Series | ID (mm) pattern |
|---|---|
| 6000 | Last 2 digits x 5 = bore (6005 = 25mm) |
| 6200 | Same rule (6205 = 25mm) |
| 6300 | Same rule (6305 = 25mm) |
For bore 20mm and above: multiply the last two digits by 5 to get the bore diameter. Example: 6208 = 08 x 5 = 40mm bore.
Send the measurements
When you send an RFQ to KIHOI with the three dimensions, we can identify the correct bearing series and offer the right replacement — even when the original part number is unreadable.