Don't forget to recalibrate your speedometer if you choose to do this.
-- Dan Meyer
I thought of that too, Dan, and noticed that they have a conversion function on the page for that.
My car takes a European sized tire, which is 185-R14. Well, once I went in to get tires
(on my way out of town on a cross-country trip), and as I headed east I noticed that a lot of people seemed to be passing me. Well, long story short, the tire place had decided to put on tire size 185-70R14, which is not the same at all. ARGH! Once I figured that out, I did some timed mileage runs and figured out that my speedometer/odometer were about 10% off, and so I was driving 10% slower than I thought. That explained all the passing.
So I went back in to the tire shop (and it was a tire shop, specifically!) on my way home and explained the problem. They refused to believe that the two tires
could be different sizes
How exasperating! I pulled some circumference figures that I had written down out of my pocket (I had a feeling they wouldn't believe me), but still no dice ("But we put this size on someone else's Volvo and they didn't mind").
They actually made me drive around with one of their technicians and a handheld GPS. Lo and behold.... about 10% off. When they ordered in the proper tires.... my, my, right on!
Since that tire size is hard to find, I've since done some calculations and found that the much easier to find North American size of 195-75R14 is almost exactly the same circumfrence as the 185-R14, so that's what I get now.)