From 18" to 17" for winter = more miles?

[Zerort]

Ok, I need a set of winter wheels for my SS. I refuse to take my car through a car wash, because they seriously scratch the face of my rims with that wheel brush. So, I want to get some wheels and tires for the winter when I do take it to the car wash. I was thinking about getting a set of 17" G6 rims.

Does anyone know if the difference in wheel diameter will cause the car to register more miles??

The 18"s are pretty tall with 225/50's on them. If I go to a 17" the diameter will be smaller unless I put a stupid tall tire on them.

Anyone know how the car measures mileage? From the trans somehow or the wheel rotation?

[EmersonHart13]

Use this to compute for yourself:

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

Wheel rotation, aka circumference is everything so try to stay close to that.

[Zerort]

That's what I figured. So looks like another set of 18's then. Oh well.

[EmersonHart13]

You can go 17s but as you know you need a taller tire...

[Interfire]

Just a question but why not just take it to a wand/touchless car wash?

[Zerort]

Just a question but why not just take it to a wand/touchless car wash?

I could, but it is kinda of a hassle when its below 32 degrees. Not to mention damn cold. But good point!

[Interfire]

Hey if I can do that up here you have no excuse

There is one near me that is heated and enclosed, so I like going there.