My car is an 04 coupe with Brembo's and OEM 18's. I just bought Enkei RPF1 rims, 18x9.5 front and 18x10.5 rear, both are +15 offset.

What is the correct tire size to use to avoid messing up the speedometer readings?

I am trying to figure it out using http://www.miata.net/garage/tirecalc.html can anyone provide the OEM tire dimensions? The stickies all talk about the wheel dimensions. Or if you flat out know what size tires I should use on the Enkei rims that works too!

 

255/40/18 and 285/40/18

 

you could use: front 255/40R18 and rear 275/40R18 wich are the realy close to the stock dimension less than 0.2% diference

 

Thanks for the help guys!

 

Is it ok if I went with thinner tires on these wheels with those specs?
Like, 255/35/18 and 285/35/18 or even
Like, 255/35/18 and 285/30/18 ?