I have 18 x 8 wheels. My options are 225/40ZR18, 225/45ZR18,245/40ZR18, and 245/45ZR18. Anything above that width and I think it would be too much. I would imagine 225 would be good for the 18, but what about sidewall? Isn't there a certain aspect ratio that I am supposed to keep? I don't know as much about tires as I should.

 

i would go with 235/40/18 just because then you are running little larger tire but not to much. and they would me cheaper then the 245

 

I would go for a 235 but its not offered apparently. I am going with the RE960AS Pole Positions. Please no one say anything about the tires...I don't care. Good all around tire, and if I lose marginal grip in exchange for a good tire thats fine. It struck me as odd that they didn't offer a 235?

 

The 245/40/18's are gonna rub unless you roll your rear arches. Even then you won't be able to run with slammed suspension and when you get 3 people in the back and corner hard it may still rub a little.

Stick to 225 or 235's

 

I bought some toyo proxie 4's from this site http://www.edgeracing.com/tire/906/

i got 225/45/17 and they were only $99 each with great all around grip =/

If it were me i would go with the toyos i liked them alot!

 

So if I am narrowed down to the 225, how do I pick which sidewall to go with? Why would I go with each?

 

http://www.miata.net/garage/tirecalc.html <-- that is your friend

 

So I would want to run a 40 if its like 4-5% closer to stock rolling circ. compared to the 45? Does the 40 vs 45 sidewall have any significant performance gains?

 

id get 235/40/18 Pzero neros or yokohama 4ws

 

225 will look narrow on a 18x8 wheel. 235/40/18 and if that's not offered in the tire then go 245/40/18 and roll the rear fenders.

 

The Pzero Neros are awesome, especially the M/S. Great grip, squeals a little when turning hard, but I never minded much.

 

235/40/18 or 245/35/18

-Mike-

 

I dont mind that really, great thing about non-super stick tires is the let you know when you are reaching their limits, unlike some that just completely break loose, thats when things get interesting