I was wondering if performance tires affect the speedometer? I currently have falken azenis on the car right now. And I think the speedometer is off about 3 or 4 mph. When im on the freeway it doesnt feel like im going 80 miles an hour. I do own a Type R btw. Thanks

 

It depends on the size of the tire. If it is smaller than stock tire than your speedo will read at a higher mph and if you are bigger than it will read lower.

 

With Azenis your speed will be off by about 5mph @ 90... so you're actually going 85 or so.

That's my experience.

 

Thanks guys.... Nice quick info.

 

You speedo is likely off with the stock tires. It and the Tach are known to read wrong. I figure smaller tires just gives me the padding to speed slightly

 

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

 

http://www.c5-corvette.com/tirecalc.htm
Best Calculator!