Plus1 sizing, or ???
 

I replaced my stock wheels with 17x7.75", +40. Now it's time to shop for tires (debating using my Primacy's though I'd prefer not to)

Since the rim is a bit wider than stock, should I go up a size in the tire? I'd like to keep a square setup. (front & back the same)

I'm likely going with Pilot SS. I'm running stock suspension. :(

Would a 225/45 tire on a 7.75" wide rim give me the same height as a 215/45 tire on a 7" wide rim?

I realize actual tire dimensions vary by tire model.

225/45/17 is +1.6% difference
225/40/17 is -2.0% difference

245/40/17 is +.4% difference(which is why you see so many people run them)

according to this http://tire-size-conversion.com/tire-size-calculator/
wheel width should not change it much if at all

Thanks! I wasn't sure if the wider wheel would "stretch" the tire a bit outwards and thus lower the height.

Will probably stay with 215's, as a 245 is wider than I need/want. (I like the lighter feel of a more narrow tire.) Now the only question I have for myself is to go back to the Primacys (in my garage, 6k miles) or spend $$$ on something more sticky.

The Ventus I bought used with the rims are so worn out the back end slides around more with TC full on than the Primacy's did in Sport mode - and that's saying something! It's like driving in the rain all the time, except its 85 degrees and sunny out.

Probably not. See: http://www.tirerack.com/tires/tires.jsp?tireMake=Michelin&tireModel=Pilot+Super+ Sport&tab=Specs. But it will be awfully close - I'd guess 24.7 vs. 24.9