If I am correct that is the tires used for the nismo rims. Just curious if the 245 40 18's and the 275 40 18's setup for the nismo rims would affect the accuracy of the speedometer? I didn't calculate it, but it would seem that the tire curcumference and height would be greater than the stock set up.

I am in the market for rims and it makes the most sense to me to get the nismos being that they were actually designed for the car.

Thanks for any help.

Gary

 

This is the setup I use. I believe it is only the rear tires that matter for speed accuracy. As you can see on this tire calculator the diff between 245/45/18 and 275/40/18 is negligable. www.miata.net/garage/tirecalc.html

 

The Outer Diameter of the stock 18s is 25.8" front and 26.8" rear. I used Dunlop SP9000s on my setup, they are 25.7" front and 26.7" rear. That's close enough for me. No speedometer error. No electronics error, just great handling. BTW, I chose the Nismos because they are a quality great looking wheel, and as you say they are designed for the car. You'll love them.

Lou

 

thanks for the replies lowrider and mcclaskz. mcclaskz, that was a very cool link, thanks.

 

Check this calculator out

http://rx7.org/public/tiresize.shtml

The only thing that it does it in MM's

 

thanks waka. havent seen you on here for a while... oh, waka just a heads up, if you are in the market for rims or tires dont buy from larry's discount mufflers. my friend just got screwed by them. They mounted the wrong size tires on his rims and they are really streached out and dont fit well. They are refusing to make it right or refund his money.

Anyways, thanks for that calculator.

Gary

 

Damn, Nice calculators!

I sat here and did the math a few times, wish I had those calculator's.

 

 

so to upgrade from the stock 17's to the nismo 18's it would require recalibration. and if this is correct how hard or expensive is it to have it done.