Changing tire size

[joeyo]

Hi all,

I currently have 13"'s on the car and I'm thinking about going up to 14"'s or 15"'s and I could have sworn I read somewhere that you needed to adjust something so that the speedometer would be correct?

I did a quick search of the forums and couldn't find anything but I think I remember Melt talking about this a few weeks ago.

Any ideas?

Joey

[Civic Jim]

the only thing u have to change is the tirewall size, depending on wot size rim u get,

I am not sure wot they are though

soemone on the forum will know though

[mightytexn]

I have 15's and have 195/50/15 tires and the speedo is almost exactly right....i calculated its off by like .1 mph or so.....this website lets you find what tire size you need http://www.miata.net/garage/tirecalc.html

[4-Door Flunky]

I put 14 inch CRX-Si rims on my 1990 LX. My tires are 185/65R14s.
I think the speedometer's very close to correct. Perhaps it shows a mile per hour more than I'm actually going, at speeds under 90 MPH. As you go faster, the amount the speedo is incorrect gets bigger.
Flunky