Originally Posted by Cmillsap

So this doesn’t make since to me because why would 245/40R18 be the correct size even tho 245/45R18 is the stock size tire for the rear wheels on the car. I also do not understand what tires have to be within the percentage. Am I only allowed to have a small percent difference between the size of the front and back tires. Or does it mean that the tires I run have to be in the percentage difference from what the stock tire size is programmed for? And if this is the case wouldn't it make it impossible to run squared wheels and tires?