Originally Posted by
ptempel
Right Front or Left Front? The usual system is to have the rear brake controlled by the lever on the side of the bicycle that corresponds to the side of the road that it will be driven on, i.e., right in most of the world; left in the British Isles, Japan, and other places where they drive on the left. (The European Union, however, has standardized on having the right-hand lever control the front brake).
https://www.sheldonbrown.com/cables.html
Sheldon adds that "
Nobody knows exactly why this is". I had heard in the past that the US product safety folks required Left-Front to reduce the likelihood of over-the-bar launches, but the Europeans preferred Right-Front (not true, though, by my observations). I have all my bikes set up as Right-Front just because I want to use my dominant hand most effectively, but I can definitely see that this could be exciting with disk brakes. I have disks on only one of my cycles and I have almost "endo'd" it more than once. Of course, it has both brake levers routed to the front.