Originally Posted by jimmuller

I'll let Sixty fill in the details but the basic issue is that threads and various other dimensions are peculiar to the French of that period. It is possible too that they switched to more conventional threading and dimensions at some point though. Upgrading wheels and crank will convert it to a very nice ride. It's pretty good as it is, very smooth, but the bike can be lightened. I happen to have a set of Sugino bearing cups with the correct threads from when I did this very upgrade to mine. If you can't find any drop me a note. I transferred my upgrade components to a different bike some years ago, including crank and spindle, but to a British-thread BB. As long as I haven't decided to upgrade it again they are available.