Originally Posted by
Kabuki12
On your bikes , they would be left hand. Italian BB are different.
Ditto for French bottom brackets; right hand threads on the fixed cup (which, as many of us have found out the hard, is far more likely to loosen spontaneously after 10 or so miles; left hand threaded British fixed cups don't do that).
Yes, all of your bikes should have the British threading,
i.e. left hand threading on the fixed cup. American and Japanese builders used the British standard for bottom brackets (probably with one or two outliers that do not matter with your three fine steeds).
As for the remove/don't remove the fixed cup debate, I am neutral. Like Switzerland. Which has it's own bottom bracket threading standard (same as the French, except left-handed thread for the fixed cup).
Bottom line: British, Italian, French and Swiss fixed cups are not compatible with each other. Swiss and French adjustable cups are the same - swap to your heart's content, but French/Swiss. British and Italian adjustable cups are not interchangeable. This silly state of affairs dates back to the days when the Alps and the English Channel posed much greater barriers to international trade than they do now.