Boundary dimensions are the fastest dependable way to remove obviously incompatible products from a bearing search. Bore diameter d, outside diameter D and width B define the physical envelope that must fit the shaft, housing and surrounding components.
Why three dimensions work together
Matching the bore alone only confirms that a bearing can pass over the same nominal shaft. A different outside diameter will not fit the housing, and a different width can change shoulder location, spacer length, preload or axial retention. A meaningful dimensional match therefore requires all three values.
Use dimensions as a filter, not a final approval
Two bearings with an identical 8 × 22 × 7 mm envelope may still use different seals, clearances, cage materials or internal geometries. Their dynamic load rating, limiting speed and temperature range can also differ. The dimensional match creates a practical shortlist; it does not complete the selection.
A repeatable comparison sequence
- Measure or confirm d, D and B from a trusted drawing.
- Search the exact dimensions and review every returned designation.
- Group results by base designation and manufacturer.
- Compare suffix meaning, load, speed, clearance and sealing.
- Check shaft and housing fits, shoulders and lubrication before approval.
This method is particularly valuable when an old bearing marking is incomplete. Dimensions can restore the likely family, while the remaining technical fields help distinguish a true candidate from a product that merely occupies the same space.