Hey guys.

I'm currently deciding whether to get 235/40/18s or 245/40/18 Goodyear F1 GS-D3's.

I prefer the 235's just because they are cheaper. Is there any reason why I should fork out more for the 245's? Apart from the fact that they look for aggressive. I also don't really mind the increased odo/speedo disparity.

I don't ever plan to track the car.

I also am planning to get new rims so want to know if I get the 235's what is the optimal rim width? I looked on the Michelin webpage that said that the optimal rim width for 235/40/18s is 8.5". I know the 245's run well on the 8.5".

I don't mind going the 8.5" but want to know if 8"s will work well too. The 8" have the added advantage of allowing the sidewalls to bulge out a little more and maybe protect my rims.
The stock Rx8 rim is 8" and i am aware many people have had success with putting on 235's onto the 8" rim.

 

if you are not going to track or auto x i would stay with the 235s....

go to tire rack.com and look at the specs... tire weight is something to think about...

also lots of people run 245s on 8" wheels no problem...

beers

 

I got the 225/40-18's, and with 20-20 hindsight I wish i'd gotten the 245's. I track them, and the extra width would have helped. Plus the 245/40 is the same diameter as the 225/45, so no odo/speedo disparity there. Also I discovered through experimentation that these have better grip and feedback at a slightly higher pressure. At 40 psi hot they were a little mushy, but at 44-45 psi hot they gripped better and gave much better audible feedback.