I was wondering how much of a difference can I have between putting new tires on vs the old set? If I am allowed or should have any at all?

For example, I am looking at these blizzaks guy is selling barely used for the end of one winter.

My current tires are P235/60/R18 and his are P235/55/R18 I figured the rim size was biggest thing in terms of different sizes. Will the 55 compared to 60 be an issue?

PS I can buy a new set, but this would save me like half of what I would spend for new set which is pretty helpful.

Topics: money, winter, snow, vehicles, tires, ice driving