I have a old 10.5 outlaw car, 120 60s and dont have no screws and just put a new set of 31-10.5 15w and they did not move inside or out. I have seen tho where tires have spun on rims that were new and only happen on ether the outside or inside. Just do what you think is best because its your but behind the wheel when something dose go wrong!
Better safe than sorry.