Straight Talk: Reader asks about tire size for cars

Credit: James Halderman

Credit: James Halderman


Bruce from Florida writes: “I have a 2004 Ford Mustang Cobra convertible and I can’t find tires that are the same size as what came on it in 2004. They are not worn out but I have been told that I should replace them because they are 16 years old. The size is 245/45X 17 and I am not able to locate these tires or at least some at a reasonable cost. Is there another size I could use? Any suggestions would be appreciated.”

Halderman: Thanks for writing. You are wise to be shopping for replacement tires. Vehicle manufacturers Ford, Nissan, Mazda and Mercedes-Benz recommend replacing tires after six years regardless of tread depth. Tire manufacturers Michelin and Continental recommends that tires that are 10 years old be replaced. Therefore, according to the industry standards, your Mustang is definitely in need of new shoes.

I checked the size comparison for various alternative sizes using an internet search and found that 255/40 X 17 will work great and should be a size that is easier to find. A couple of websites that can be helpful include:

Best wishes in locating new tires and enjoy your convertible.

Have an automotive question? Get a straight answer by writing to Jim at

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