Proper tyre sizes would help - in the format AAA/BB/CC where 'AAA', 'BB' is the profile as a percentage of the width, and 'CC' is the tyre diameter in inches.
I'm guessing it will give you something like 225/40/18 and 255/40/18 or similar.
I'm also guessing that the top picture of the tyre tread and wheel is not your's.