So I ordered my new wheels and i went from the stock 19's to 20's.
When I ordered the wheels and tires I requested 245/30/20's. front and 275/30/20's rear.

I noticed that everyone who has the coupe with 20's runs 245/35/20's instead of the 245/30/20's with the 275/30/20's. Is their a reason for this fitment or is it just a looks thing?

I always thought you would keep the series the same front and back, maybe someone with more knowlede than me can share the reasoning........

 

I think it's something along the lines of keeping the radius almost equal to each other.

 

That front tire is going to be TINY! You're going to want to return it for sure.

Tire sidewall heights are a ratio of the over treadwidth (the 3 digit number)

Sooo. a 245/35 tire is technically the same height as a 265/30.

So, your 275/30 and your 245/30 are going to be a very different size, you should have upped the sidewall height in order to compensate for the fact that the tread width is thinner.

 

You can see the difference using a tire size calculator:

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

or

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

Tire sizes may vary slightly between different manufacturers.

But it would look alright as long as the wider tire, therefore taller tire is in the rear.

 

Thanks for the info guys..makes sense now. I actually looked at my reciept of purchase and they had sent me the 245/35 anyway. They are at the depot I pick them up and put them on Friday, cant wait.

 

+ ^^ and ^^^. I hope the 245/35's do come in.