17 inch wheels

[2win2rbo]

^With those tyres, I would really decrease my corner entry and exit speed. Anyway, I will have to change my tyres maybe after 2 or 3 years. I would just maximize what I can in my 100% city driving. If I get at least 5% highway, my mpg shoots up easily.

[CapriRacer]

Dealing with tire sizes and fuel economy is pretty complex. You may want to consider that larger load carrying capacity tires when used at the same inflation pressure have better F/E. In other words, narrower isn't always better - sometimes wider is.

Also, there is more to be gained from selecting tires with good rolling resistance values. unfortunately, these gains come from traction and treadwear. Careful selection should be made to properly balance these 3 properties.