I have 17 inch rims on my 2005 toyota matrix. If i replaced the rims with 16 inch rims would it improve my mpg

Yep, especially in the city. you won`t have to press the pedal down so far to take-off. Unless you get fatter tires and the overall diameter doesn`t change.
I have 17 inch rims on my 2005 toyota matrix. If i replaced the rims with 16 inch rims would it improve my mpg
mcdbert is right. As long as you're lowering the dimension of the wheel and tire, you're improving the 'final drive ratio'... Smaller tires take less effort to turn.





You may also end up decreasing curb weight, which will help even more.
I have 17 inch rims on my 2005 toyota matrix. If i replaced the rims with 16 inch rims would it improve my mpg
No.





Look at the EPA estimated mileage for Toyota Matrix models fitted with 16 and 17-inch wheels.





They are the same.





Even if it did save you some miniscule percentage of fuel how much fuel would you have to save to pay for the $800-1,000 in wheels and tires you would need to buy? Your chances of braking even don't even rank.

ginkgo