Currently i

 

BlueS2000,

Why would you want to go skinnier?

I am running 215/40/18 and 245/35/18 and I am dying to go 225 and 255.

 

Phantom,

I heard that the stock front tires , which are 205, correspond to real "195" size , the rear tires, that are 225 , are real "245".Ok then...
Being so, with the tires i

 

BlueS2000,

O.k., I wouldn't give too much thought over the stock S02 205 = regular 195 and stock S02 225 = regular 245.

The first number (225/50/16) means nothing other than the section width from a tire's sidewall to sidewall. That means that two tires that are 225/50/16 can have verry different tread widths sizes.

What kind of 245/40/17's are you running? I bet if you take a ruler and measure the actual tread that is touching the ground on your 245's and compare it with the stock S02's, you will find that the stock S02's will be wider.

I am running 245/35/18 Toyo T1-S and the rear tread that is touching the ground is no where near the measurement of the stock S02's.

I think you are doing fine with your 215/45/17 and 245/40/17. If you have enough offset on your wheels, you could even go 225/45/17 and 255/40/17.