What are the actual pros? Cons, if there are any........

 

pros: wider is better. more tire, more grip. 245's also look a bit nicer
remember to go 245 /40

cons: price?
some people say the steering doesn't feel as precise. (though having owned both sizes, I disagree with 245 feeling numb)

 

does this knock the speedometer off any?

 

Not by much.

http://www.miata.net/garage/tirecalc.html

 

^ thanks

 

I just had a set of BF Goodrich g-force T/A KDW (245/40/18) tires on my 8 and I am totally impressed. I've been through the canyon roads in Malibu twice now, and there is a huge difference from stock. Lots of grip and they look way better.

But do as Jedi say: if you switch from 225's to 245's, you should switch from a 45 series profile to a 40 series profile. This will ensure that you have a similar rolling diameter and the least amount of speedometer error.

I had to explain this to COSTCO b/c they didn't want to install a non-stock sized tire. I had to show them that the rolling diameter and height profile was nearly identical to stock for them to do it.

 

245's will also have more spring back when hitting the tight turns. So you are more **** to lose controll of the car if you are not use to sliding when thitttting them turns. The ones I had on 18"x8 with a 40 off set where fat tires and the side walls where soft.
So yea +1 with the 40 side wall.

 

sure.

beers

 

Hi guys, can I ask a total noob question? I can't understand how you can chose from a variety of tire sizes like 225 or 245 for a wheel? Shouldn't there just be one possible size that reflects the width of the wheel? I mean it's obvious that's not the case or this thread wouldn't exist, but could someone explain why? Thanks all!!

 

What about 235 series tires, 235/40-18? Besides 225 or 245 we have this option available to us as well.

 

the outside dia of the 225 / 45 / 18 is 25.9in.

that is what to shoot for..

tire rack is a great source of info.. on any tire and size.

beers