i realize that 45 is the recommended series for 16 inch wheels on an ITR, but i was wondering...

shouldn't it be 205/45 and 215/40?

i mean, isn't the series a percentage of the width, so a 215/45 would have more sidewall than a 205/45?

i was just wondering what people had with 16 inch rims on all your cars...for some reason discount tire keeps telling me i need 215/40s. any pictures or assistance would be appreciated.

 

correct. 40/45 is the ratio of the side wall compared to the width of the tire.

 

so would 215/40s be the correct set up to go with?

 

As a general rule, you should get tire sizes whose outer diameter is as close to stock as possible. So if you have bigger wheels and wider tires, you normally want an aspect ratio (that's the 40 or the 45) that's low enough to keep the outer diameter the same.

Outer diameter in inches:
195/55-15 (stock): 23.44
215/45-16: 23.61
215/40-16: 22.77

In terms of outer diameter, you'd be better off with 215/45-16 than 215/40-16.

Of course, you're also limited to the sizes of tires that are available.