the 57-62 range is the sweet spot..
the focus has plenty of power to step up to taller with bigger tread.
62 is still slow for todays highways. I could sincerely guess 195/65/15 needed .. if not there already, if so, fill out those wells one size up.
I went a bit extreme with this concept on an old subaru...the sweet spot was moved into 78-92.. yes, miles an hour.
65 is barely the 2850 rpm needed for max oil pump. it is a little buggy to remember..
