What size tire on a 15x4 inch rim ?

Using a 165/80x15 on a 3 1/2 centerline on one car, 165/80 on a 15x4 rocket spoke, 185/65x15 on the other (also 3 1/2 cl). The 185 were all I could find the day I needed tires to make a race. Very short, a little too wide.... but they work.