This is not a homework problem. I have been thinking of this for a while now. I am only in physics 2 my professor isn't smart as he thinks he is. I want to figure out how to calculate the gas milage difference from tire size. I would like help to point me in the right direction in order to solve this. What i think i need to use for this.. I know i am wrong but hopefully someone can point me in the right direction. I was thinking we would need to know the rotational kinetic energy, while having friction of being on a road. But how do I find the power base off of kinetic energy? I think this would be absolutely amazing if I could figure this out.