at the moment i have 175/70-14 tires on the front wheels of my Valiant, these are around 24".....and they do look definitely too small. I´d go at least 25" or 26" in the front (will change to 175/80-15 next off-season, these are 26").
Before the widespread of transmission brakes, most 4-tenths Pro-tree racers ran a 24" tire on front.
I had them on my Super Street Duster in 1990.
Heck if they had made a 18" tire, we would have found a way to use them. LOL