Another factor for those thinking outside the LBS box is that ALL bike sealed
bearings are standard sizes, readily available from quality (non Chinese) sources.
Bearing suppliers are all over the internet and if one sticks to industrial suppliers
as opposed to suppliers to bike shops, BMXers, roller blades etc you are highly
likely to get good quality bearings. Bearings are characterized by ID, OD and
thickness and type of seal. These will invariably be exact millimeter sizes. The
existing bearing will have an alphanumeric designater on the seal somewhere that
can give you a head start but the ID/OD/thickness is fundamental.