Odometer/tire size question

[Me]

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?

[Rob]

is there a tire placard on the door post near the VIN tag?

"Me" <Dont...@me.here> wrote in message
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