Ball Bearing Sizes.

[neptune]

I have been doing a lot of bike tinkering lately, and thinking about replacing bearings, such as hubs, bottom bracket and steering head bearings.Looking at the old Sheldon Brown articles, things look simple.All sizes are shown as fractions of an inch; rear hubs and bottom brackets are a quarter, and front hubs are three sixteenths.

I would be surprised if these sizes were standard throughout the world.Few of the bikes on our streets are made in the UK. Many are made in China, India etc. So the big question is, do some countries use metric sizes?

 

[oigoi]

Ones I've dismantled have all been imperial but only way to know for sure what you've got is take them out and measure them

 

[flecc]

Probably all Imperial still, it dominates bicycles in things like wheel, tyre and chain dimensions and pitch, so the Chinese producing bicycle parts will be familiar with it. Even many things often expressed as metric like handlebars are actually just metric conversions of Imperial, 25.4mm being one inch and 31.8mm being one and a quarter inches.
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