I have a 2005 Chrysler 300C AWD and used one of those roadside odometer tests the other day and found a discrepancy. After driving five kilometers, the odometer read that I had gone six. That is a 20% difference. I assume that this means that my current tires are 20% smaller than they should be, or there is a mechanical failure somewhere. Am I correct? I don't recall what size tires are on the car. The web identifies 225/60R18 as the correct tire size. Using a tire calculator, 20% smaller diameter would end up being a 145/45R18 or a 165/45R17. It's not likely to be THAT different. So, what should I be looking at here?
