KOYO vs RKB: equivalent part numbers

Most bearings, sleeves, nuts and housings are designated by standard: ISO for metric series, and the UC/UCP designation that every brand uses for housings with insert bearings. That is why the same code in two brands means the same series and the same main mounting dimensions: bore, outside diameter and width, or the housing dimensions.

What can differ between brands are the suffixes: sealing or shielding, internal clearance, cage, grease or tolerance. Each manufacturer writes them its own way, so the equivalence is confirmed with the full designation, not just the base number.