17" rims and fuel economy

[thebarber]

Originally Posted by MadMax

My Yaris has 215/45ZR17 tires on it, and stock tires are 175/65R14s.

Go to this web site and submit those two sizes in, and you will see that the stock tire has a circumference of 72.09 inches (1831mm) whereas the larger tire I am running has a circumference of 77.31 inches (1963.6mm). That's a diameter difference of 6.75%.

Do the math and you will see the tire travels a distance of an additional 5.22 inches per rotation over the stock tire.

As the odometer is set for the stock tire, you must add the addition of 7% (rounded up) to the odometer distance traveled.

it is suggested you dont go past 3% tire size difference....just because it screws up your speedometer and odometer too much otherwise...