205 or 215-50=13 tires are excelent tires for 13x7 and 13x8 wheels.60 or 70 tires tend to go too tall and rub up against fenderwells and other parts. Check the tire rack site at
www.tirerack.com for tires and you will see you can find 195-50-13. 205-50-13 and 215 50 13 in a couple of brands like sumitomo and t/a bf goodrich among others. If you want to lower your
car,50 series is a must and 13-50's work well.15 inch tires are too big for this cars,in my personal opinion do not look nice,and the car does not enjoy the benefit of a lowered suspension
because it can not be lowered enough unless you are a body specialist in which case a new and larger fender-tire-well is put in place,or else cheat yourself with one of those aero
fiberglass kits wrap arounds that all they do is wrap your car in fiberor plastic parts,anything but lower the car for the weight and air factor you are looking for. It is just my
opinion,thanks and enjoy your Datsun.