Also, if tuning hubs that have cartridge bearings, remember that there are sealed, shielded, and unshielded variants in each size. Sealed has more dragthan shielded, which has more drag than unshielded. If ordering from a bearing wholesaler, you can also get "one side sealed", "one side sealed, one shielded", ...
You just have to do some digging through their catalogs to find exactly what you want. This is a good site to learn about different types and the nomenclature system in place to identify them.
https://www.astbearings.com/radial-ball-bearing-nomenclature-and-numbering-system.html
Pro Tip: when installing bearings, face the labelled side outward so that you can identify the bearing without having to remove it.
Last edited by taras0000; 01-03-19 at 08:42 AM.