Originally Posted by CivicSiRacer
You will always get better mpg with a ligher wheel and tire. MOst of the time when you plus size the wheel AND tire get heavier which takes more energy/fuel to turn.
I know my 16x7.5" Kosei K1s with Azenis were about 42lbs. My 15x7" Kosei K1s with Azenis were 34lbs.
not exactly true. If you somehow ran an 11" wheel as opposed to a 15" wheel you would lose gas mileage even though they are lighter. if you set gear ratios aside 1 revolution of the motor would equal 1 revolution of the tires. a larger wheel would take you farther per each revolution. (didnt anyone else build mousetrap cars back in elementary school?) The weight part however will slightly effect mileage if you were comparing wheels of the same size. as long as youre not going from a stock wheel to a 25lb bohemoth (spelling) you wont notice much difference at all.
I went from hx wheels to 17" enkei rs6 (20lbs a piece per rim) and the change wasnt noticeable.