Originally Posted by
verktyg
French threads have the smallest outside diameter. ISO, British and Italian freewheels will start to thread on but will bind up after a few turns. If those freewheels are forced on they will damage the metric threads and can spin off under load destroying the hub.
Are you sure you don't have that backward? I'm experiencing the opposite, I think. French threaded freewheels will start to thread onto non-French threaded hubs, but will bind after a few turns.