New 07 Yaris S need advice on 18's and springs

[Black Yaris]

Originally Posted by OgDogg

18's with 215/35 tires are nearly the same size as the stock 15's on this car. Having bigger rims will just improve cornering and looks. If you get a set of racing 18's you might even improve fuel economy. I'm going to test my mpg before/after when my 18's get here next week. I'll be surprised if I lose much efficiency. The look of the car will far outweigh any minor decreases in fuel efficiency if there is any. Not to mention those of us who slap 18's on a Yaris are probably doing things to increase engine output anyway. My question is why not put 18's on a Yaris? After more carefully looking over the specs and talking with other custom Yaris owners, I sort of regret not going with 19's and no lowering kit.

my question to you is, what are you on, and why ain't you sharing?
fact (1) is a 215/35 is slightly smaller than stock, to stay exactly stock diameter you would go with a 225-30-18....

fact (2) if you have a wheel, one in an 15 inch and one in 18 inch, exact same wheel only different sizes, the 18 will weigh more, unless you did find the one wheel manifacture that makes wheel out of a substance lighter than air, then I stand corrected, added weight decreases gas mileage

fact (3) a 225-50-15 will corner better than a 225-30-18, why you ask? side wall flex.... I will explain... To keep traction on the road during a high G turn the tire needs to flex to keep the contact patch to the road. A 225-30-18 has 1.5 inches less side wall than the 225-50-15 therefore has less flex in the sidewall, therefore can not corner as fast or as sharp as one with 225-50-15

Ask anyone who truely races they will tell you the same

16's on up on a Yaris, all show, no go